FIVE  YEARJ 
QUESTIONS  AND  ANSWERS 

NATIONAL  ASSOCIATION  OF 
STATIONARY  ENGINEERS 


V  -  ;  i   •: 


National  Association  of 
Stationary  Engineers 

Five  Years  Questions 
and  Answers 


As  originally  published  in  The 
National  Engineer 


VOLUME    TWO 


First    Edition 


Chicago: 

P.  F.  PETTIBONE  &  CO.,  Printers 
1908 


Copyright  1908 

by 
FREDERICK.  W.  RAVEN,  Nat'l  Sec'y 


FOREWORD 


This  volume  contains  the  Questions  and  Answers  of  the  course 
carried  on  by  the  National  Educational  Committees  of  the  National 
Association  of  Stationary  Engineers  during  the  years  1902  to  1906, 
inclusive. 

It  is  practically  volume  2  of  the  work  so  widely  and  favorably 
known  as  the  "Five  Years'  Questions  and  Answers,"  published  by 
the  National  Association  of  Stationary  Engineers  in  1902. 

The  object  of  this  volume  is  to  present  information  for  engi- 
neers in  such  a  manner  as  will  convey  the  necessary  information 
clearly  and  yet  concisely. 

There  has  been  added  to  the  regular  educational  work,  a  series 
of  tables  which  of  themselves  form  a  modest  work  of  reference. 

This  volume  was  compiled  by  the  National  Educational  Com- 
mittee for  1907-1908.  Messrs.  Chas.  W.  Naylor,  Otto  Luhr  and 
F.  J.  Roos,  all  of  Chicago,  and  members  of  Illinois  Nos.  28,  38 
and  2,  respectively. 


NATIONAL   ASSOCIATION  OF   STATIONARY   ENGINEERS. 


QUESTIONS  AND  ANSWERS 

1902-1906. 


Engines. 


Q.  1.     Describe,  in  a  general  way,  a  simple  slide-valve  engine. 

Ans.  1.  A  simple  slide  valve  engine  has  three  port  openings,  one  for  ex- 
haust steam,  and  two  for  the  admission  of  steam  to  each  end  of  the  cylin- 
der. The  slide  valve  is  so  fitted,  then  when  at  the  center  of  its  travel,  it 
covers  both  steam  and  exhaust  ports;  it  is  actuated  by  means  of  a  valve 
rod  and  an  eccentric  rod  driven  by  an  eccentric,  the  latter  being  mounted 
upon  the  engine  shaft.  The  motion  of  the  eccentric  communicated  to  the 
valve  moves  the  latter  so  that  when  steam  is  being  admitted  to  one  end 
of  the  cylinder,  the  other  end  of  the  cylinder  is  open  to  the  exhaust  port; 
this  operation  taking  place  twice  in  each  revolution. 


Q.  2.  How  early  is  it  possible  to  cut  off  steam  on  this  type  of  en- 
gine, and  what  limits  early  cut-off! 

Ans.  2.  Steam  cannot  be  cut  off  earlier  than  half  stroke  in  this  type 
of  engine.  The  reason  for  this  is  that  the  valve  has  to  perform  the  double 
function  of  admitting  as  well  as  exhausting  the  steam,  and  in  order  to  do 
this  properly  for  both  strokes  of  the  engine  the  eccentric  must  be  placed 
at  a  90  degree  angle  from  the  crank;  the  relative  positions  of  eccentric 
and  crank  preventing  an  earlier  point  of  cut-off  than  one-half  stroke. 


Q.  3.     How  may  cut-off  and  compression  be  changed  in  a  simple  slide- 
valve   engine? 

Ans.  3.     (a)     Cut-off  may  be  made  earlier  by  increasing  the  outside 
lap. 

(b)  Cut-off  may  be  made  later  by  decreasing  outside   lap. 

(c)  Compression  may  be   made   greater  by  increasing  the  inside  lap. 

(d)  Compression  may  be  lessened  by  decreasing  the  inside  lap. 


Q.  4.  Define  clearance  and  explain  its  effect  on  the  economy  of  the 
engine. 

Ans.  4.  Clearance  includes  all  space  between  the  piston  and  cylin- 
der head  when  piston  is  at  the  extreme  point  of  travel,  a;so  the  space  of 
passages  for  the  admission  of  steam  between  admission  valve  and  cylin- 
der, and  between  cylinder  and  exhaust  valve. 

These  spaces  must  be  filled  with  steam  every  stroke,  and  as  the  steam 
used  to  fill  the  clearances  does  no  appreciable  amount  of  work  it  is  con- 
sidered as  a  loss.  In  other  words,  the  greater  the  clearances  the  greater 
the  loss. 


Q.  5.  What  is  the  object  of  having  a  valve  riding  on  the  back  of  a 
slide-valve  and  in  what  way  does  it  affect  the  valve-gear  of  the  engine? 

Ans.  5.  The  object  of  having  one  valve  ride  on  the  back  of  a  slide 
valve  is  to  secure  a  point  of  cut-off  earlier  than  half  stroke.  This  is  ac- 
complished by  having  each  valve  driven  by  a  separate  eccentric;  the  rid- 
ing valve  determining  the  point  of  cut-off  while  the  main  valve  controls 
the  admission  and  exhaust  to  and  from  the  cylinder. 


Q.  6.  If  a  properly  proportioned  slide-valve  is  so  set  as  to  give  too 
much  lead  on  one  end  and  none  on  the  other,  what  effect  will  it  have  on  the 
operations  of  the  valve  and  what  will  remedy  it? 

Ans.  6.  It  will  make  the  cut-off  late  and  the  compression  early  on 
the  end  having  excessive  compression,  and  the  cut-off  early  and  compres- 
sion late  on  the  other  end. 

The  remedy  is  to  shorten  or  lengthen  the  valve  stem  as  the  case  may 
require. 


Q.  7.     What  is  understood  by  the  term  "a  balanced  slide-valve?" 

Ans.  7.  A  balanced  slide  valve  is  one  with  surfaces  so  arranged  that 
the  steam  in  the  steam  chest  acts  to  balance  the  valve,  preventing  the 
steam  from  pressing  the  valve  on  its  seat,  as  is  the  case  with  a  plain  slide 
valve. 


Q.  8.     State  what  advantage,  if  any,  there  is  in  using  the  forced  system 
of  lubrication  on  engines,  for  both  internal  and  external  work. 

Ans.  8.     The   advantage   of    forced   feed    of   lubrication   is   the   saving 
in  oil;   positive  feed  and  more  uniform. 


Q.  11.  What  is  the  difference  between  a  piston  valve  and  a  flat  slide 
Talvef 

Ans.  11.  A  piston  valve  consists  of  one  or  more  pistons,  without 
packing,  mounted  upon  a  rod  or  spindle,  and  usually  designed  to  cor- 
respond with  annular  spaces  in  valve  chests.  In  construction  this  type 
of  valve  may  be  either  single  or  multiported,  it  may  or  may  not  have 
lead  or  lap,  and  is  generally  considered  as  being  balanced. 


A  flat  or  slide  valve  is  made  in  one  piece,  and  has  one  or  more  cham- 
bers on  the.  inner  face,  and  is  commonly  known  as  a  D.  or  B.  valve.  Its 
design  is  such  that  it  controls  the  admission,  cut-off,  compression  and  re- 
lease of  the  steam,  and  is  not  balanced. 


Q.  12.  What  are  the  advantages  of  a  four-valve  engine,  and  a  plain 
slide  valve  engine! 

Ans.  12.     The   advantages    of    a    four-valve    engine    are    as    follows: 

Good  distribution  of  steam,  resulting  in  better  economy,  due  to  the 
independent  action  of  each  valve  relative  to  opening  and  closing. 
Cylinder  drainage  is  well-nigh  perfect  owing  to  the  position  of  the  ex- 
haust valves  being  at  the  bottom  of  the  cylinder,  as  in  the  Corliss  type 
of  engine.  Full  benefit  of  expansion  of  the  steam,  by  admitting  it  at 
approximately  boiler  pressure  and  maintaining  same  up  to  point  of  cut- 
off, which  is  always  automatic  and  proportionate  to  tbe  load  of  the  en- 
gine. This  type  possesses  the  advantage  of  being  easily  started  or 
etopped  and  is  easily  manipulated. 

The  advantages  of  a  plain  slide  valve  consist  of  its  low  first  cost, 
ite  mechanical  simplicity,  ease  of  putting  it  together,  adaptability  to 
portable  outfits,  quiet  running  under  light  loads  owing  to  the  fixed  point 
of  compression,  and  ease  of  maintenance. 


Q.  13.    (a)     Describe  a  gridiron  valve. 

(b)  Describe  a  poppet  valve. 

(c)  Describe  a  Corliss  valve. 

Ans.  13.  (a)  A  gridiron  valve  is  a  slide  valve  having  one  or  more 
parts,  arranged  to  correspond  with  the  ports  leading  to  the  cylinder,  and 
designed  to  give  a  short  travel  and  rapid  movement  in  opening.  It  is 
classed  as  a  multiported  valve. 

(b)  A  poppet  valve  consists  of  one  or  more  discs  mounted  on  a  stem 
or  spindle,  and  in  operation  moves  in  a  vertical  plane,  raising  and  drop- 
ping over  the  corresponding  valve  seat  or  seats. 

(c)  A  Corliss  valve,  as  the  name  is  now  applied,  consists  of  the  seg- 
mental   parts  of  a  cylindrical   casting  which   is  made   to  partly  rotate  in 
a  circular  chamber;  and  is  called  a  semi-rotative  valve.     The  construction 
may  be  either  of  single  or  multiported  design,  or  may  be  arranged  to  ad- 
mit steam  through  an  opening  in  its  center. 


Q.  14.  What  range  of  cut-off  is  permissible  on  a  four-valve  engine, 
where  all  valves  are  operated  by  one  eccentric? 

Ans.  14.  In  a  four-valve  engine  of  the  Corliss  type,  for  example, 
where  all  the  valves  are  operated  by  one  eccentric,  the  range  of  cut-off 
will  be  from  zero  to  about  one-half  stroke. 


Q.  15.     With  a  single  eccentric,   as   mentioned    in   the   preceding   ques- 
tion, why  cannot  a  long  range  of  cut-off  be  obtained? 

Ans.  15.     Because    the    eccentric    being    set    90    degrees    ahead    of    the 
crank,  reaches  the  extreme  poir.t  of  its  throw  by  the  time  the  piston  ha? 


reached  the  half-stroke,  therefore  cut-off  must  occur  before  that  time. 
Owing  to  the  angularity  of  the  connecting  rod,  however,  it  is  possible  to 
have  the  cut-off  occur  later  than  half-stroke,  particularly  on  the  head 
end  of  the  engine.  If  the  steam  valves  are  set  "late"  it  will  also  serves 
to  give  a  late  cut-off. 


Q.  16.     How  may    a    four-valve    engine,    with    two    eccentrics,    be    ad- 
justed to  obtain  a  late  point  in  cut-off? 

Ans.  16.     A  late  point  of  cut-off  may  be  obtained  by  taking  the  lap 
off  the  steam  valve  and  setting  back  the  steam  eccentric. 


Q.  17.  Describe  a  force  feed  method  for  lubricating  steam  engine, 
pump  or  air  compressor  (steam  end)  cylinders. 

Ans.  17.  A  force  feed  lubricator  consists  of  a  mechanically  oper- 
ated pump  to  force  the  oil  into  the  feed  pipes  leading  into  the  steam  chest 
and  cylinders,  the  pump  is  operated  by  connecting  to  some  moving  part 
of  the  engine  and  the  pump  can  be  adjusted  to  feed  the  required  amount. 


Q.  18.     Enumerate  some  of  the  advantages  to  be  derived  from  a  point 
of  cut-off  late  in  the  stroke. 

Ans.  18.     It  allows  taking  care  of  overloads  under  the  control  of  the 
governor. 


Q.  19.  Under  what  conditions  would  it  be  more  economical  to  operate 
a  single  cylinder,  non-condensing  engine,  than  a  cross  compound, 
condensing  engine,  assuming  the  load  to  be  500  h.  p.,  the  run  each  day  to 
be  nine  hours? 

Ans.  19.  It  would  be  more  economical  to  run  single  cylinder  and  non- 
condensing  engine.  When  you  have  to  buy  water  for  your  condenser  and 
where  you  can  use  the  exhaust  steam  for  heating  purposes,  dry  kilns,  etc. 


Q.  20.'   What  closes  the  steam  valves  of  a  detachable    valve    gear  en- 
gine? 

Ans.  20.     Steam  pressure  on  area  of  valve,  steam  vacuum  dash  pots, 
springs,  and  weight  dash  pots. 


Q.  21.     Give  five  reasons,  any  one  of  which  may  cause  a  fly  ball  type 
or  steam  engine  governor  to  fail  to  regulate  the  speed  of  the  engine. 

Ans.  21.     Five  reasons  for  a  fly  ball  governor  not  working  would  be: 

1.  Belt  break  or  fly  off. 

2.  Packing  too  tight  on  stem. 

3.  Pin   in   Governor   too    short. 

4.  Bevel  gear  loose  on  pulley  shaft. 

5.  Dash    pot   out    of    order. 


Q.  22.     Why   are   not   detachable   valve   gears  used  on   high  speed   en- 
jfinesf 

Ans.  22.     They  would  not    be    able    to    engage    when    running    faster 
than  100  R.  P.  M. 


Q.  23.  If  you  were  running  a  four  valve  engine  non-condensing  and 
desired  to  have  same  run  condensing,  what  change  in  the  valve  setting 
would  you  make? 

Ans.  23.  Close  the  exhaust  valves  earlier  in  the  stroke,  giving  almost 
twice  as  much  compression. 


Q.  24.  What  effect  would  changing  from  non-condensing  to  con- 
densing have  on  the  engine,  in  relation  to  its  developing  power f  What 
would  be  the  effect  from  an  economy  standpoint  and  whyf 

Ana.  24.  It  would  depend  on  what  the  cooling  water  cost.  When 
water  can  be  obtained  at  little  cost  there  is  from  10%  to  25%  saved  on 
fuel. 


Q.  25.     Is  the  crosshead  pressure    greater  on  the    guide    of    a    vertical 
engine  than  on  a  horizontal  engine?     Give  reasons. 

Ans.  25.     It  should  have  read,  "No,  except  the  weight  of  piston  rod, 
crosshead  and  connecting  rod." 


Q.  26.  How  does  the  length  of  the  connecting  rod  as  compared  with 
that  of  the  crank  affect  the  pressure  of  the  crosshead  upon  the  guide? 

Ans.  26.  A  short  connecting  rod  causes  a  greater  strain  on  cross- 
heads.  The  usual  length  of  connecting  rod  is  about  five  or  six  times  the 
length  of  crank. 


Q.  27.  How  would  you  disconnect  a  crosshead  from  a  piston  rod  where 
the  connection  between  both  was  by  means  of  a  key? 

Ans.  27.  Remove  the  key.  Place  the  engine  on  crank  end  dead  cen- 
ter. Connect  a  pump  with  crank  end  of  cylinder  and  force  the  rod  out 
of  the  crosshead  with  hydraulic  pressure. 

CORRECTIONS. 

The  following  is  a  correction  in  the  answer  to  question  No.  27,  as  it 
appeared  in  the  March  number  of  The  National  Engineer: 

Remove  the  key;  then  by  the  use  of  a  male  and  female  gib,  with  taper 
key  between  them,  inserted  in  slot  with  male  gib  next  to  the  crosshead. 
A  few  sharp  blows  with  a  hammer  will  start  the  crosshead  off  the  pin. 
Another  way  is  to  remove  the  crosshead  pin  and  insert  a  press  as  follows : 
Take  a  piece  of  round  iron  as  large  as  will  go  in  pinhole  with  a  hole 
drilled  and  tapered  as  large  as  possible.  Make  a  long  thread  screw  so  it 
will  reach  from  end  of  piston  rod  in  crosshead  out  far  enough  to  get  a 
wrench  on,  and  then  you  can  press  off  most  any  crosshead  made. 


Q.  28.     Is  lead  necessary  iu  a,  steam  engine! 

Ans.  28.  In  a  pump  without  a  fly  wheel  or  in  a  steam  hammer  lead 
is  desirable  and  in  a  very  slow  running  engine  it  may  be  useful  but  in 
the  ordinary  type  of  engines,  lead  is  not  necessary  as  the  momentum  of 
the  rotating  parts  will  move  the  piston  forward  until  the  valve  can  open 
and  put  steam  into  the  cylinder. 


Q.  29.  Given  two  engines  using,  respectively,  15  and  30  pounds  of 
stoam  per  indicated  horse  power:  All  other  conditions  being  the  same, 
which  engine  will  show  the  greater  increase  in  economy,  when  using  steam 
with  150  degrees  superheat? 

Ana.  29.  The  engine  that  uses  the  greatest  weight  of  steam  per  in- 
dicated horse  power  will  be  benefited  the  most  when  using  steam  with 
150°  F  superheat,  because  the  volume  of  steam  required  is  the  same  in 
any  engine  all  other  conditions  being  equal. 


Q.  30.  What  pressure  should  there  be  in  the  receiver  of  a  non-con- 
densing, cross-compound  engine,  when  the  engine  is  running  at  one-half  its 
rated  speed  and  without  load? 

Ans.  30.     None  that  could  be  indicated  by  a  steam  gauge. 


Q.  31.  What  examination  of  an  engine  should  an  engineer  make,  on 
assuming  charge  of  same,  to  assure  himself  that  it  is  in  condition  to 
operate  properly? 

Ans.  31.  An  engineer  on  taking  charge  of  a  strange  plant  should 
make  a  sufficiently  thorough  examination  to  ascertain  if  the  engine  is  in 
fair  working  order.  Such  examination  should  include  testing  the  piston 
for  leakages,  examination  of  the  cylinder  for  evidences  of  cutting  or 
scoring,  testing  valves  for  leakages  and  general  condition  as  to  wear, 
etc.,  inspecting  the  adjustment  and  condition  of  all  bearings,  noting 
valve  adjustments  and  connections,  turning  engine  over  by  hand  to  ascer- 
tain clearance  spaces  of  piston,  carefully  examining  the  oiling  devices  for 
both  internal  and  external  lubrication,  and  inspecting  the  governor  to  see 
if  it  is  in  proper  working  order.  After  thorough  examination,  with  the 
engine  at  rest,  steam  should  be  admitted  to  warm  cylinder,  after  which 
the  engine  can  be  started  slowly  and  gradually  brought  up  to  speed. 


Q.  32.  How  would  you  determine  whether  an  engine  connecting  rod 
was  of  the  correct  length  to  give  an  equal  clearance  at  each  end  of  the 
engine  cylinder? 

Ans.  32.  Disconnect  the  connecting  rod  from  crosshead  and  place  the 
piston  at  the  extreme  end  of  cylinder.  While  piston  is  in  this  position 
make  a  corresponding  mark  on  the  guide  and  crosshead  for  reference. 
Then  place  piston  at  other  extreme  end  of  cylinder,  and  likewise  place 
a  corresponding  mark  on  guide  and  crosshead  to  designate  point  of  ex- 
treme travel.  Now  connect  up  the  connecting  rod,  and  place  engine  on 

10 


one  center.  Then  carefully  note  the  difference  in  extreme  travel  of  piston 
as  compared  with  the  marks  previously  made  on  crosshead  and  guide. 
Place  engine  on  other  center  and  repeat  operation.  In  this  way  the 
clearance  at  each  end  may  be  readily  ascertained.  If  the  amount  is 
greater  on. one  end  than  on  the  other,  it  may  be  equalized  by  one  of  two 
methods.  If  the  piston  rod  is  screwed  into  the  crosshead,  and  secured 
by  jam  or  lock  nuts,  the  rod  may  be  turned  around  a  sufficient  number 
of  times,  either  forward  or  back,  to  bring  the  piston  to  a  position  that 
will  equalize  the  clearances;  it  being  understood,  of  course,  that  there 
is  a  limit  to  the  number  of  turns  a  rod  should  be  moved  in  either  direc- 
tion. In  turning  the  rod  around  care  should  be  taken  to  see  that  the 
piston  does  not  have  to  assume  a  new  position  in  relation  to  its  wearing 
places  in  the  cylinder;  in  other  words,  the  rod  should  "DC  turned  fully  one 
complete  turn  and  not  fractional  parts  of  same. 

Where  the  piston  rod  is  attached  to  the  crosshead  by  means  of  fixed 
key  or  wedge,  the  equalization  of  clearance  spaces  may  be  brought  about 
by  using  shims  at  the  stub  ends  of  the  connecting  rod. 


Q.  33.      (a)     What    is    a    throttling    governor? 

(b)  What  is  an  inertia  governor f 

(c)  What  is  meant   by   "governor   range"! 

Ans.  33.  (a)  In  a  governor  of  the  fly-ball  type  so  constructed  that 
when  the  engine  attains  more  than  a  specified  speed,  the  fly-balls  are 
forced  outward,  thereby  forcing  a  spindle  attached  to  a  valve  downward, 
and  by  this  action  reducing  the  pressure  of  the  steam  admitted  to  the 
cylinder,  and  partially  shutting  off  the  steam  until  the  engine  resumes 
its  normal  speed,  when  the  governor  assumes  a  different  plane,  either 
high  or  low,  depending  upon  the  amount  of  steam  needed  to  keep  engine 
up  to  speed. 

(b)  An     inertia     governor    is    of     the     shaft    or    wheel    type     and    is 
usually  placed  within  or  adjacent  to  one  of  the  driving  or  balance  wheels 
of  the  engine.     When  the  shaft  is  turning  at  a  constant  speed,  the  only 
forces  tending  to  make   the   governor  weights   change  their  position   rela- 
tively are:  First,  centrifugal  force;  second,  the  pulling  action  of  a  springj 
and  third,  resistances  due  to  the  connection  of  the  governor  weights  with 
the   eccentric,    and   these   latter   must   be   in   equilibrium.     As   soon,   how- 
ever, as  the  speed  of  the  governor  shaft  and  governor  wheel  changes,  the 
tendency  of  the  governor  weight  or  weights  to  continue  at  the  same  speed 
in   consequence    of   inertia,   comes   into   play,   and   the   accelerating    forces 
are  thus   developed  which  may   aid   or  oppose   the   centrifugal   action,  de- 
pending on  the  design  of  the  governor. 

(c)  Long   range  governors  control   the  point  of  cut-off  from   zero  to 
about   7/10  of  the  stroke,   while  short  range  governors  control   from   zero 
to  about   V>  stroke. 


Q.  34.  Explain  the  difference  between  automatic  cut-off,  and  throt- 
tiing-governed  engines,  also  the  advantages  of  one  method  over  the  other. 

Ans.  34.  The  difference  between  a  throttling  governor  and  an  au- 
tomatic governor  is  that  the  former  reduces  the  steam  pressure  accord- 
ing to  the  load,  while  the  volume  of  steam  admitted  to  the  cylinder  re- 
mains constant,  thus  causing  a  wire-drawing  action;  whereas,  with  the 
automatic  type,  steam  at  approximately  boiler  pressure  is  admitted  to 
the  cylinder  up  to  the  point  of  cut-off,  this  point  being  determined  by  the 
governor  according  to  the  engine  load,  and  the  remainder  of  the  stroke 
completed  by  expansion,  making  the  latter  method  the  more  economical 
in  the  use  of  steam. 

11 


Q.  35.     Regardless    of    design,    into    how   many   classes    are   steam    en- 
gines divided? 

Ans.  35.     Condensing  and   non-condensing. 


Q.  36.  What  advantage  is  it  to  have  two  eccentrics  on  a  condens- 
ing engine  f 

Ans.  36.  The  use  of  two  eccentrics  permits  of  having  the  steam 
and  exhaust  valves  separately  actuated,  and  in  such  a  manner  as  to  per- 
mit of  range  of  cut-off  being  independent  of  the  opening  and  closure 
of  exhaust  valves,  thus  allowing  the  latter  to  be  set  to  secure  any  de- 
sired amount  of  compression. 


Q.  37.  What  is  the  difference  between  a  surface  condenser  and  a  jet 
condenser? 

Ans.  37.  A  surface  condenser  is  so  constructed  that  the  exhaust 
steam  does  not  come  into  direct  contact  with  the  cooling  water,  but  ia 
condensed  by  coming  into  contact  with  metal  surfaces  cooled  by  the  cool- 
ing water.  This  is  generally  accomplished  by  discharging  the  exhaust 
steam  in  a  receptacle  having  a  number  of  small  tubes  through  which  the 
cooling  water  circulates.  Their  installation  is  generally  for  the  two-fold 
purpose  of  saving  the  water  of  condensation  and  keeping  the  latter  in 
good  condition  for  return  to  the  boilers. 

With  a  jet  condenser,  the  exhaust  steam  and  the  cooling  water  mingle, 
resulting  in  quick  condensation.  In  many  cases  the  injection  water  used 
renders  the  combination  unfit  for  boiler  feed  water. 


,  Q.  38.  Why  do  we  sometimes  fail  to  realize  the  proper  receiver  pres- 
sure, during  the  first  half -hour's  run,  of  a  cross-compound  condensing 
engine? 

Ans.  38.     Leaks  in  L.  P.  valves  which  take  up  when  all  parts  get  hot. 


Q.  39.     What    is    a    compound    engine? 

Ans.  39.  A  compound  engine  is  one  which  expands  steam  in  two  or  more 
cylinders.  If  expanded  in  three  cylinders  it  is  called  a  triple  expansion; 
if  in  four  cylinders  it  is  called  quadruple  expansion. 


Q.  40.     Why   are  compound   engines   used? 

Ans.  40.  To  obtain  the  advantage  of  high  pressure  steam,  and  at 
the  same  time  avoid  the  losses  due  to  cylinder  condensation  as  much  as 
possible. 

If  the  steam  be  allowed  to  expand  in  two  or  more  cylinders,  the  fall 
in  temperature  is  divided  between  the  cylinders,  consequently  the  loss 
from  condensation  is  considerably  less. 

12 


Q.  41.     What  types  and   designs  of   compound   engines  are  in   general 
ef 

Ans.  41.     Horizontal,  upright,  tandem  and  cross-compound. 


Q.  42.  (a)  Where  no  receiver  is  used  in  connection  with  a  com- 
pound engine,  at  what  angle  are  the  engine  cranks  set,  one  with  the 
other? 

(b)  Where  a   receiver  is  used,   what  will   the  relative  angle   of  the 
cranks  be,   and  whyf 

(c)  Why    are    not    receivers   used    in    connection    with    tandem    com- 
pound engines f 

Ans.  42.  (a)  At  the  same  angle,  or  at  180°.  (b)  Steam  can  be 
taken  from  the  receiver  at  any  angle  of  the  stroke,  therefore  the  cranks 
may  be  set  at  any  angle,  in  relation  to  one  another,  (c)  Because  the 
steam  exhausts  from  the  high  pressure  to  the  working  side  of  the  low 
pressure  piston. 


Q.  43.  What  advantage  is  there  in  a  compound  engine  over  a  single 
engine,  where  the  service  conditions  are  such  that  the  engine  must  ex- 
haust against  a  gauge  pressure  of  five  pounds! 


Ans.  43.     Not   any. 


13 


Boilers. 


Q.  1.  Which  is  preferable — -a  diagonal  or  a  through  and  through  stay? 
Why? 

Ans.  1.  Through  and  through  stays  are  preferable  in  so  far  as 
strength  of  the  boiler  is  concerned,  as  they  pull  in  the  direction  of  the 
stress,  but  their  use  is  objected  to  on  account  of  the  inconvenience  they 
cause  to  any  person  entering  the  boiler;  for  this  latter  reason  diagonal 
stays  are  very  often  preferred. 


Q.  2.  Describe  what  you  believe  to  be  the  most  correct  method  for 
conducting  an  inspection  of  a  horizontal  return  tubular  boiler. 

Ans.  2.  The  hammer  test  is  most  correct  but  should  be  done  by  one 
of  experience  so  that  he  can  readily  detect  by  the  sound  whether  the 
braces  have  the  proper  tension  or  whether  corroded  or  pitted  or  blistered 
or  the  plates  are  sound  and  should  ba  tested  inside  and  outside.  The 
hydraulic  test  may  be  used  in  connection  if  desired. 


Q.  3.  What  causes  a  horizontal  return  tubular  boiler  to  "pulsate" 
in  its  setting;  a  kind  of  breathing  action,  as  it  weref  And  at  what 
time  is  such  action  apt  to  be  discernible  f 

Ans.  3.  Pulsation  of  a  boiler  is  caused  by  weakness  and  want  of 
capacity  in  the  boiler  to  supply  the  necessary  quantity  of  steam,  sometimes 
caused  by  a  boiler  being  poorly  designed.  It  is  discernible  most  when- 
ever forcing  the  fire  in  order  to  keep  steam  at  the  required  point. 


Q.  4.  Why  are  not  rivets  made  larger  and  spaced  farther  apart, 
in  order  to  remove  as  small  an  amount  of  metal  as  possible. 

Ans.  4.  If  rivets  were  spaced  farther  apart,  the  plate  would  spring 
between  rivets  when  caulking,  making  it  impossible  to  make  the  joint 
steam  or  water  tight. 


Q.  5.     How  are  tubes  fastened  to  boiler  heads  and  made  tight? 

Ans.  5.  Tubes  are  fastened  to  boiler  heads  by  being  rolled  or  ex- 
panded, and  the  ends  beaded  over  to  form  a  slight  flange,  enabling  the 
tube  to  hold  to  the  heads  against  the  internal  pressure  in  the  boiler. 

14 


Q.  6.  What  form  of  tool  is  used  in  caulking  seams  and  why?  State 
effect  of  using  improperly  shaped  tool. 

Ans.  6.  A  flat  thick  chisel  with  rounded  edges  is  used  in  caulking 
seams.  A  tool  of  that  shape  upsets  the  edges  of  the  plates  without  cut- 
ting them.  A  sharp  edged  tool  would  cut  the  surface  of  the  under  plate, 
and  also  leave  a  place  liable  to  be  attacked  by  corrosion. 


Q.  7.     How  are  manholes  reinforced? 

Ans.  7.  Manholes  are  reinforced  by  having  a  ring  of  castiron  or 
Bteel  of  sufficient  strength  to  take  the  stress  off  that  part  of  the  boiler, 
riveted  to  the  plate;  or  by  having  the  plate  itself  flanged  and  thus  form- 
ing a  strengthening  rim  around  the  manhole. 


Q.  8.  Why  is  the  wide  strap  in  a  double  butt  strap  seam  placed  on 
the  inside! 

Ans.  8.  Triple  riveted  double  butt  strap  joints  have  the  outside 
rows  of  rivets  spaced  twice  as  far  apart  as  the  other  rows,  and  with  one 
strap  wide  enough  to  take  in  this  outside  row  of  rivets.  This  wide  strap  is 
placed  on  the  inside  in  order  that  the  caulking,  which  is  done  on  the  out- 
side, may  be  done  on  the  double  sheet  and  on  the  straps  having  the  rivets 
closer  together,  thus  avoiding  any  springing  of  the  plate.  Placing  the 
wide  straps  on  the  inside  allows  the  boiler  pressure  to  be  exerted  on  th« 
larger  area  with  less  liability  to  leakage. 


Q.  9.  Under  average  service  conditions  which  is  the  most  economical 
for  boiler  feeding,  an  exhaust  injector  or  an  ordinary  duplex  steam  pump! 
In  these  cases  it  is  assumed  that  there  is  ample  exhaust  steam  to  operate 
the  injector,  and  that  the  pump  delivers  water  to  a  feed  water  heater, 
which  raises  the  temperature  of  the  water  to  190°  F. 

Ans.  9.  An  exhaust  injector  would  be  more  economical  to  use  above 
the  Duplex  feed  pump,  when  you  have  no  special  use  for  the* exhaust 
steam,  of  about  15%. 


Q.  10.  Why  are  rivets  in  double  shear  not  twice  as  strong  as  rivets 
in  single  shear! 

Ans.  10.  It  is  probable  that  if  the  stress  could  be  equally  divided  be- 
tween the  two  shearing  sections  of  the  rivets,  that  rivets  in  double  shear 
would  be  twice  as  strong  as  the  same  rivets  in  single  shear,  but,  owing 
to  the  uncertainty  of  having  the  stress  equally  divided,  due  to  imperfect 
alignment  of  holes  in  practical  boiler  work,  it  would  not  be  safe  to 
allow  for  rivets  in  double  shear,  more  than  185  per  cent  of  the  allowable 
stress  for  the  same  rivets  in  single  shear. 


Q.  11.     Why  are  some  boiler  and  tank  heads  cupped  out  I 

Ans.  11.     Boiler    and    tank    heads    are    sometimes    cupped    outward    to 
do    away    with   the    necessity    of    staying.     With    this    form    of    head   the 

15 


strength  is  not  wholly  dependent  on  its  stiffness,  but  part  of  the  stresi 
on  the  head  is  tensile  strength,  which  makes  this  form  of  head  much 
stronger  than  a  flat  head. 


Q.  12.  Are  straight  tubes  or  curved  tubes  preferable  in  water  tube 
boilers? 

Ans.  12.  Straight  tubes  are  preferable  to  curved  tubes  in  water 
tube  boilers,  because  they  are  easier  to  clean  and  inspect,  and  give  a  more 
direct  passage  for  the  circulation  of  water,  as  well  as  being  easier  to  re- 
place. 


Q.  13.  How  are  the  nipples  connecting  tube  headers  and  saddle  piece 
in  a  B.  &  W.  boiler  fastened? 

Ans.  13.  The  nipples  connecting  tube  headers  and  saddle  piece  in  a 
B.  &  W.  boiler  are  expanded  in  the  headers  and  saddle  piece,  and  the  endi 
flared  or  bellied  out  to  fasten  them. 


Q.  14.     How  are  the  tube  caps  put  on  a  B.  &  W.  boiler! 

Ans.  14.  (a)  Tube  caps  on  B.  &  W.  boilers  are  put  on  the  outside 
and  held  in  place  by  a  bolt  with  a  cap  nut,  the  bolt  passing  through  a 
yoke  or  yoke  plate  inside  the  tube  header.  The  joints  between  the  cap 
and  header  and  between  cap  and  nut  are  ground.  Generally  a  little  oil 
and  graphite  to  make  the  joint  tight  and  occasionally  a  thin  paper  gasket 
is  used  for  this  purpose. 

(b)  In  the  latest  type  of  B.  &  W.  boiler  the  caps  are  placed  on  the 
inside  similar  to  a  hand-hole  plate  in  a  return  tubular  boiler. 


Q.  15.  What  results  may  be  noted  when  the  mud  drum  of  a  B.  & 
W.  boiler  rests  upon  the  brick  work? 

Ans.  15.  Should  the  mud-drum  of  a  B.  &  W.  boiler  rest  upon  the 
brickwork  it  will  sustain  the  weight  of  the  boiler  when  heated,  caused  by 
expansion  of  headers  and  nipples;  these  parts  will  then  sustain  the  weight 
of  the  rear  of  the  boiler,  generally  causing  the  nipples  to  start  in  head- 
ers and  saddle  piece,  resulting  in  serious  leaks.  The  mud-drum  should 
never  rest  on  the  brickwork. 


Q.  16.  When  is  a  drift  pin  used  in  boiler  construction?  Why  is  its 
use  detrimental  to  good  workmanship? 

Ans.  16.  In  boiler  construction  a  drift  pin  is  sometimes  used  to 
force  carelessly  spaced  rivet  holes  into  line  so  that  the  rivet  may  be  driven 
in.  This  distorts  the  rivet  holes  and  causes  strain  in  the  metal  near  the 
holes,  which  makes  the  use  of  a  drift  pin  detrimental  to  good  work- 
manship. 


Q.  17.     Explain  different   methods   of  staying  crown  sheet  of  locomo- 
tive type  of  boiler. 

16 


Ans.  17.  There  are  two  methods  generally  followed  in  staying 
crown  sheets  of  locomotive  type  of  boilers.  The  first  is  by  means  of 
girder  stays  commonly  called  "fox  roof  stay."  The  ends  of  these 
girder  stays  rest  upon  the  edge  of  side  sheet  of  fire  box;  a  number  of  stay 
bolts  pass  through  crown  sheet  and  girder  stay  secured  at  both  ends  with 
nuts  and  washers,  thereby  staying  the  crown  sheet.  The  ends  of  girder 
stay  are  turned  down,  thereby  causing  a  small  water  space  between  it  and 
the  crown  sheet. 

A  second  method  is  by  having  stay  bolts  pass  through  crown  sheet 
and  secured  as  in  the  first  method;  but  the  other  end  of  bolt  has  a  forked 
end  and  pin  fastened  to  angle  irons  which  are  riveted  to  shell  of  boiler. 


Q.  18.     In  a  longitudinal  lap   joint,  why  does  the   outside   sheet  point 
upward,  and  the  inside  sheet  downward! 

Ans.  18.     To  prevent  scale   lodging   on    same — inside   of  boiler. 


Q.  19.  What  method  is  used  to  detect  a  defective  stay  bolt  as  used 
on  the  side  sheets  of  a  locomotive  type  of  boiler  f 

Ans.  19.  Stay  bolts  staying  flat  surfaces  very  generally  will,  when 
giving  out,  fracture  near  the  outside  shell.  By  drilling  a  small  hole  in 
stay  bolt,  where  protruding  through  outside  shell,  water  and  steam  will 
rush  out  of  hole  when  fracture  occurs,  exposing  the  location  of  the  de- 
fective bolt.  Stay  bolts  are  now  in  the  market  having  small  holes  drilled 
into  both  ends. 


Q.  20.  What  are  the  usual  methods  for  inserting  stay  bolts  for  con- 
necting flat  surfaces? 

Ans.  20.  Stay  bolts  connecting  flat  surfaces  of  a  boiler  are  usually 
threaded  the  whole  length  and  secured  through  both  plates,  and  their 
ends  beaded  over;  sometimes  that  portion  of  the  stay  bolt  between  the 
plates  has  the  thread  turned  off  smooth  to  prevent  the  lodgment  of  scale 
on  the  thread. 


Q.  21.  Explain  methods  of  connecting  inner  and  outer  sheets  of  water 
leg  of  vertical  tubular  boiler.  Which  one  method  is  the  most  preferable, 
and  why? 

Ans.  21.  The  inner  and  outer  sheets  of  water  leg  of  a  vertical  boiler 
are  connected  by  a  wrought  iron  ring  which  forms  a  distance  piece  separ- 
ating the  plates.  Cast  iron  is  sometimes  substituted,  but  wrought  iron 
is  preferable.  Another  method  is  by  using  a  wrought  iron  double 
flanged  ring.  This  is  not  to  be  recommended,  as  it  leaves  a  narrow  ridge 
on  top  of  ring  where  sediment  collects.  This  sediment  is  difficult  to  re- 
move. 


Q.  22.     Which  is  preferable,   short   or  long  diagonal  stays?     Give  rea- 
sons. 

Ans    22.     A   long   diagonal   stay  is  preferable  to  a  short   one   as   the 
stress  is  more  nearly  in  line  with  its  length. 

17 


Q.  23.  How  are  through  and  through  braces  usually  fasteued  in  a 
boiler? 

Ans.  23.  Through  and  through  stays  are  usually  fastened  with  a  nut 
and  washer  on  both  inside  and  outside  of  head.  The  ends  of  rods  where 
threaded  are  enlarged  so  that  the  cross  sectional  area  at  bottom  of  thread 
will  be  at  least  equal  to  cross  sectional  area  of  the  rod. 


Q.  24.  When  inspecting  a  boiler,  how  can  one  ascertain  whether  all 
through  and  through  braces  are  under  uniform  tension? 

Ans.  24.  The  tension  on  through  and  through  stays  may  be  judged 
by  the  sound  given  out  when  struck  with  a  hammer.  A.  similar  tone  from 
each  indicates  a  uniform  tension,  while  a  dull  tone  indicates  less  tension. 


Q.  25.  Why  is  a  reinforcing  plate  used  where  the  blow-off  pipe  en- 
ters a  boiler? 

Ans.  25.  A  reinforcing  plate  is  used  where  the  blow-off  pipe  enters 
boiler  to  give  greater  thickness  of  metal  to  screw  the  blow-off  pipe  into. 
If  the  hole  into  the  shell  is  too  large  to  fit  the  pipe,  the  main  object  of  the 
reinforcing  plate  is  defeated,  for,  although  the  plate  strengthens  the 
shell  around  hole,  its  main  object  is  to  better  secure  the  blow-off  pipe  into 
the  shell  by  means  of  more  threads. 


Q.  26.  Give  reasons  for  and  against  the  use  of  a  submerged  tube 
sheet  in  a  vertical  tubular  boiler. 

Ans.  26.  The  submerged  tube  sheet  in  a  vertical  tubular  boiler  has 
the  advantage  of  protecting  the  upper  end  of  tubes  from  the  action  of 
the  fire.  Its  disadvantages  are  a  small  steam  space  and  a  tendency  to 
prime  when  boiler  is  forced;  they  are  then  apt  to  carry  water  into  the 
steam  mains. 


Q.  27.     Of     what    material    are    boiler    lugs    made?       How    are    lugs 
fastened  to  boiler? 

Ans.  27.     Boiler  lugs  on  horizontal  tubular  boilers  are  made  of  cast 
iron  and  riveted  to  the  shell. 


Q.  28.  How  many  lugs  should  be  attached  to  a  boiler?  Give  rea- 
sons. 

Ans.  28.  Not  more  than  two  lugs  should  be  attached  to  each  side  of 
the  boiler,  no  matter  what  the  length  of  the  same  may  be.  If  more  wer« 
used  uneven  settling  of  brick  work  might  throw  all  the  weight  upon  the 
middle  lug,  causing  a  great  strain  upon  boiler. 


Q.  29.     Explain  the  circulation  of  water  in  a  B.  &  W.  boiler. 

Ans.  29.  The  circulation  of  water  in  a  B.  &  W.  boiler  is  from  front 
to  rear  of  steam  drum,  down  rear  tubes  and  headers,  thence  through 
inclined  tubes  to  front  headers,  up  through  front  headers  and  into  steam 
drum. 

18 


Q.  30.  Why  are  the  mud  drums  of  B.  &  W.  boilers  usually  made  of 
cast  iron! 

Ans.  30.  Cast  iron  is  used  as  the  impurities  of  the  water  do  not  so 
readily  attack  cast  iron  as  they  do  wrought  iron  or  steel;  and  therefore, 
cast  iron  better  resists  corrosion.  In  boilers  built  for  high  pressure  steel 
and  wrought  iron  are  sometimes  used. 


Q.  31.  How  should  a  fusible  plug  be  constructed,  and  of  what  mate- 
rial T 

Ans.  31.  The  body  or  shell  is  made  of  brass,  threaded,  standard 
pipe  size,  %",  1"  or  1^4".  The  hole  through  the  plug  is  made  conical 
to  prevent  the  fusible  metal  being  forced  out  by  the  pressure;  the  large 
end  of  the  cone  being  always  on  the  pressure  side.  The  small  end  of 
the  cone  should  not  be  less  than  l/2  inch  in  diameter.  Banca  tin  has 
been  found  to  be  the  most  reliable  metal  to  use  for  the  cone.  Its  melt- 
ing point  is  about  445  degrees  F. 


Q.  32.     Where  should  a  fusible  plug  be  placed  in  the  following  types 
of  boilers? 

a.  Horizontal  tubular. 

b.  Vertical   tubular. 

c.  Locomotive. 

d.  Babcock    &   Wilcox. 

Ans.  32.  a.     In  a  drop  pipe  from  top  of  shell  or  in  backhead  above  tubes. 

b.  In  one  of    the  tubes    about  2     inches    below  the  lower    gauge 
cock,  a  hand     hole     being    cut    through    the    shell    for    the    purpose    of 
inserting  the  plug. 

c.  In  crown  sheet. 

d.  In  a  drop  tube  through  top  of  shell. 


Q.  33.  What  precautions  should  be  observed  in  cutting  a  boiler  in 
on  the  steam  main  which  is  under  pressure;  also  when  a  boiler  in  to  be 
cut  out  under  the  same  conditions? 

Ans.  33.  The  precautions  observed  should  be  to  have  steam  brought 
up  equal  to  pressure  in  main,  and  all  pipe  connections  should  be  well 
drained  and  by  pass  (if  any)  opened  to  allow  the  pressure  to  equalize 
before  opening  the  main  valve,  and  should  be  opened  very  cautiously  at 
all  times,  and  to  cut  out  the  fire  should  be  drawn  or  very  low  and  valve 
then  closed. 


Q.  35.     When  a  steam  boiler  is  equipped  with  two   pop  safety  valves, 
should  the  blowing  point  of  each  be  the  same? 

Ans.  35.     When  two  pop  valves  are  used  on  one  boiler  one  should  be 
slightly  in  advance  of  the  other. 


Q.  36.     What    precautions   should   be    observed    when    laying   up    a   re- 
turn tubular  boiler  for  an  extended  period  of  time? 

19 


Ans.  36.  Blow  out  boiler ,  while  warm  and  clean  out  thoroughly  and 
if  in  a  dry  place  leave  off  man  hole  and  hand  hole  plates.  If  in  a  damp 
place  cover  the  inside  of  the  boiler  with  black  oil.  Remove  all  ashes  and 
soot  in  direct  contact  with  the  shell  of  the  boiler. 


Q.  37.  In  steam  boiler  practice,  neglecting  the  efficiency  of  the 
butt-strap  joint  over  the  lap  joint,  name  two  other  decided  advantages 
of  the  former  over  the  latter  type  of  joint. 

Ans.  37.  The  strains  are  more  directly  in  the  line  of  the  metal  and 
the  plates  are  not  injured  to  so  great  an  extent  in  the  rolling. 


Q.  38.  Does  the  normal  steam  pressure,  or  the  expansion  and  con- 
traction due  to  furnace  operation,  cause  the  greater  strain  in  steam  boil- 
ers I 

Ans.  38.  Expansion  and  contraction  cause  the  greater  strain  on  a 
steam  boiler  because  of  the  enormous  strain  that  must  take  place  where 
there  is  unequal  heating;  or  the  heating  and  cooling  effect  of  ordinary 
operation. 


Q.  41.  If  a  spring  loaded  safety  valve  is  set  at  one  hundred  pounds, 
what  is  the  method  of  procedure  to  alter  the  blowing  point  to  sixty 
pounds! 

Ans.  41.  If  a  spring-loaded  safety  valve  operates  all  right  at  100 
pounds'  pressure  it  will  be  necessary  to  change  the  spring  for  a  lighter 
one,  in  order  to  operate  successfully  at  60  pounds'  pressure,  as  these 
springs  should  not  be  operated  at  a  greater  variation  than  15  or  20  per 
cent. 


Q.  45.  Where  and  how  should  a  feed  water  pipe  enter  the  follow- 
ing types  of  boilers? 

a.  Horizontal  tubular. 

b.  Vertical   tubular. 

c.  Babcock  &  Wilcox. 

Ans.  45.  (a)  The  feed  pipe  may  enter  the  boiler  through  top  of 
shell  near  front  end,  or  through  front  tube  sheet  just  above  the  top  row 
of  tubes;  in  either  case  the  pipe  should  be  of  brass  and  should  extend 
to  near  the  back  end  of  boiler  and  deliver  the  water  below  the  water  line. 

(b)  The    feed    pipe   should   enter   the    boiler   through   the    shell    near 
the   low  water  line,   should   extend   across   the   boiler   between   the   tubes, 
should  be  of  brass,  the  end  should  be  capped  and  the  pipe  perforated  to 
distribute  the  water. 

(c)  The  feed  pipe  should  enter  front  of  steam  drum  below  the  water 
line  and  extend  some  distance  back  into  the  drum. 


Q.  46.  Describe,  in  from  75  to  125  words,  the  special  features  and 
principles  involved  in  the  construction  of  the  "Heine"  water  tube  boiler. 

Ans.  46.  The  Heine  Safety  Boiler  has  all  flange  steel  construction, 
without  the  use  of  expanded  joints  to  hold  any  of  the  parts  together,  with 
the  exception  of  the  tubes.  There  are  no  cast  iron  parts  under  tensile 

20 


stress.  The  water  legs,  constructed  somewhat  similar  to  the  side  sheets 
in  a  locomotive  type,  have  a  tendency,  owing  to  their  ample  areas,  to 
give  more  rapid  circulation.  The  trend  of  the  combustion  gases  is  hori- 
zontal through  the  nest  of  tubes.  The  external  side  of  tubes  is  cleaned 
by  means  of  a  steam  blower  inserted  through  the  hollow  stay  bolts  in 
front  and  rear  water  legs.  Tube  caps  are  on  inside  of  water  leg  mak- 
ing joint  similar  to  an  ordinary  handhole. 


Q.  47.  Describe,  in  from  75  to  125  words,  the  special  features  and 
principles  involved  in  the  construction  of  the  "Cahall"  water  tube  boil- 
ers, both  vertical  and  horizontal  type. 

Ans.  47.  The  Cahall  Vertical  Water  Tube  Boiler-  consists  of  two 
drums  arranged  one  above  the  other  and  connected  with  a  nest  of  tube*. 
The  upper,  or  steam  drum,  has  an  opening  in  the  center  through  which 
gases  pass  to  chimney.  The  boiler  rests  upon  four  iron  brackets  riveted 
to  lower  drum,  supported  upon  four  piers  of  the  foundation.  The  boiler 
is  allowed  freedom  of  expansion  without  interfering  with  external  brick 
work.  The  tubes  are  straight  and  placed  in  a  vertical  position,  with,  a 
slight  outward  deflection  from  bottom  to  top,  owing  to  the  upper  drum 
oeing  of  slightly  larger  diameter  than  the  lower  drum.  Owing  to  the 
central  hole  in  upper  drum,  there  is  a  space  in  center  of  tubes,  wide  on 
top  and  gradually  narrowing  down  towards  bottom.  This  boiler  has  an 
external  combustion  chamber,  and  takes  up  very  little  floor  space.  It 
is  extensively  used  in  places  where  waste  furnace  heat  is  available,  such 
as  steel  mills,  etc. 

The  horizontal  type  of  Cahall  boilers  is  of  the  sectional  header  type, 
such  as  the  B.  &  W.  The  Cahall  boilers  are  fitted  with  swinging  manhole 
covers.  They  swing  on  hinges,  and  the  lifting  in  antl  out  of  the  covers 
is  thereby  avoided. 


Q.  48.  Why  will  a  fusible  plug  melt  when  covered  with  steam,  and 
the  same  plug  not  melt  when  covered  with  water,  all  other  conditions  being 
the  same? 

Ans.  48.  When  a  fusible  plug  is  covered  with  water,  the  heat  en- 
tering the  plug  from  the  fire  is  absorbed  by  the  water;  but  when  plug  is 
covered  with  steam,  the  steam  will  not  absorb  the  heat  entering  plug, 
owing  to  the  fact  that  steam  is  only  able  to  absorb  heat  less  than  one- 
third  as  rapidly  as  water. 


Q.  49.  What  do  you  consider  the  best  manner  to  temporarily  stop 
the  leak  of  a  split  tube  in  a  fire  tube  boiler  in  order  to  avoid  a  shut 
down! 

Ans.  49.  A  pine  plug,  the  end  of  which  should  snugly  fit  the  tube, 
and  the  center  turned  to  a  smaller  diameter.  Drive  the  plug  into  tube 
until  the  leak  stops,  then  drive  some  little  distance  further,  some  two  or 
three  inches  until  the  leak  will  be  opposite  the  turned  part. 


Q.  50.  If  the  crab  and  nut  of  rear  hand  hole  plate  in  a  horizontal 
tubular  boiler  should  burn  off  would  there  be  any  danger  of  blowing 
water  out  of  boiler? 

21 


Ans.  50.  The  burning  off  of  a  crab  and  nut  would  not  allow  water  to 
blow  out  of  boiler  as  long  as  the  handhole  plate  itself  is  intact,  for,  aa 
these  plates  are  put  on  from  the  inside,  the  pressure  holds  them  firmly  in 
place. 


Q.  51.     How  may  crabs  and  nuts  of  rear  hand  hole  plate  be  protected 
from  the  fire? 

Ans.  51.     By  covering  nut  and  crab  with  asbestos  or  fire  clay. 


Q.  52.  Why  is  good  circulation  of  water  in  a  boiler  essential  to 
good  steaming! 

Ans.  52.  Water  is  practically  a  nonconductor  of  heat.  The  heated 
water  therefore  does  not  impart  the  heat  it  receives  to  its  surround- 
ing particles.  However,  when  heated  it  expands,  thereby  becoming  of  a 
lesser  specific  gravity  than  the  cooler  particles.  This  heated  water  will 
endeavor  to  rise  while  the  colder  portions  come  to  be  heated  in  turn,  thua 
setting  up  currents  in  the  water.  The  better  the  facilities  in  a  boiler  are 
for  setting  up  these  currents  or  "circulation,"  the  more  efficient  will  be 
its  steaming  qualities  and  its  safety  in  operation. 


Q.  53.  Does  the  water  level,  as  shown  in  gauge  glass,  always  rep- 
resent the  true  level  in  boiler,  all  connections  being  clear  and  openf 

Ans.  53.  If  the  water  in  the  gauge  glass  and  its  connections  could 
be  kept  at  the  same  temperature  as  the  water  in  boiler,  it  would  represent 
the  true  level,  but  as  the  water  in  glass  and  connections  cools  off,  it  be- 
comes of  a  greater  density,  and  of  course  heavier  than  a  corresponding 
amount  of  warmer  water  would  be.  The  water  contained  in  glass,  there- 
fore, will  be  able  to  balance  a  column  of  greater  height  of  warmer  water. 
When  water  gauge  and  connections  are  exposed  in  a  cool  place,  and  par- 
ticularly so  if  the  connections  are  long,  the  difference  of  the  glass  level 
and  boiler  level  become  more  pronounced.  There  are  known  instances 
of  the  difference  being  some  1%  to  2  inches.  That  is,  the  water  in  boiler 
would  be  ll/2  to  2  inches  higher  than  that  shown  in  glass.  Immediately 
after  thorough  blowing  down  of  glass,  the  true  level  will  be  shown  until 
water  begins  to  cool  off. 


Q.  54.      (a)     If  top  of  gauge  glass  is  shut  off  what  is  the  result? 
(b)'    If  bottom  of  gauge  glass  is  shut  off  what  is  the  result? 

Ans.  54.  (a)  By  shutting  off  top  valve  of  gauge  glass  the  steam 
is  prevented  from  entering  glass;  the  steam  contained  in  glass  will  almost 
immediately  condense,  allowing  the  water  to  take  its  place  and  rapidly, 
in  fact,  almost  instantly  filling  the  glass. 

(b)  By  shutting  off  bottom  valve  of  gauge  glass  the  water  is  pre- 
vented from  entering  the  glass;  the  steam  in  top  of  glass  as  it  condenses 
will  slowly  fill  the  glass. 


Q.  57.     Why  do  pop  safety  valves  remain  open  some  time  after  boiler 
pressure  has  been   reduced  below  the  point  at  which   they   open? 


Ans.  57.  Owing  to  the  beveled  edges  of  the  valves  and  seat,  the 
steam  after  opening  the  valve  is  allowed  to  act  upon  a  larger  area  than 
when  valve  is  closed,  therefore  the  valve  will  blow  until  the  steam  has 
fallen  to  a  pressure  too  low  to  balance  this  larger  area. 


Q.  74.     Describe  in  from  75  to   125    words    the    special    features    and 
principles  involved  in  the  construction  of  the  Iowa  boiler. 

Ans.     74 The    Iowa    boiler    combines    in   its   construction    the    return 

tubular  and  the  water  tube  type  of  boiler.  The  upper  part  consists  of  an 
ordinary  multi-tubular  boiler.  The  lowrer  part,  being  of  the  water  tube 
type,  is  connected  to  the  upper  part  by  two  water  legs  made  in  the  form 
of  an  arch,  the  tubes  connecting  the  legs  from  the  sides  and  top  of  fur- 
nace and  combustion  chamber.  Fire  brick  between  tubes  and  fire  clay 
plastering  keep  furnace  and  combustion  chamber  tight  on  sides  and  top. 
The  tubes  in  lower  part  are  inclined  up  towards  rear,  and  circulation  ia 
through  the  tubes,  up  rear  leg,  through  main  shell  and  down  through  front 
leg.  Impurities  in  the  water,  precipitated  in  the  upper  shell,  can  do  no 
harm,  as  the  shell  is  not  in  contact  with  the  fire  or  combustion  gases.  The 
rear  of  combustion  chamber  and  rear  of  tubes  in  upper  shell  are  con- 
nected by  means  of  a  short  flue  for  the  passage  of  the  combustion  gases 
from  lower  to  upper  part  of  boiler. 


Q.  75.  Describe  in  from  75  to  125  words  the  special  features  and 
principles  involved  in  the  construction  of  a  Stirling  boiler. 

Ans.  75.  The  Stirling  boiler  consists  of  three  steam  and  water 
drums  at  the  top  and  one  water  or  mud  drum  at  the  bottom.  Each  top 
drum  is  connected  to  bottom  drum  by  a  bank  of  tubes  slightly  curved 
at  the  ends.  The  steam  spaces  between  the  upper  drums  and  the  water 
space  between  front  and  middle  drums  are  also  connected  by  means  of 
tubes.  Suitable  fire  brick  baffle  plates  between  the  banks  of  tubes  direct 
the  course  of  the  furnace  gases.  The  feed  water  enters  rear  top  drum, 
the  coolest  part  of  the  boiler,  and  its  temperature  is  gradually  raised 
in  its  descent  through  the  rear  bank  of  tubes  to  mud  drum  below.  The 
lower  drum  is  protected  from  the  furnace  heat  by  the  bridge  wall,  and  the 
drum  being  large  and  the  circulation  therein  very  slight,  it  acts  as  a 
settling  chamber  for  the  impurities  precipitated  there  by  the  feed  water  as 
it  enters  the  drum,  descending  to  the  bottom  of  drum  where  they  can  be 
blown  off  through  the  blow-off.  The  drums  have  manholes  at  each  end, 
The  boiler  is  made  of  wrought  material  throughout. 


Q.  77.     What  causes  bagging  in  a  boiler  plate? 

Ans.  77.  Bagging  of  a  boiler  plate  is  caused  by  overheating,  gen- 
erally due  to  scale  or  other  deposits  accumulating  to  an  extent  that  pre- 
vents the  water  from  coming  in  contact  with  the  plate.  The  plate  then 
becomes  soft  and  easily  yields  to  the  pressure  acting  upon  it,  thereby 
forming  a  bag.  A  plate  in  such  condition  is  materially  weakened  and 
liable  to  be  rent  asunder,  causing  an  explosion. 


Q.  79.     What   is   meant   by  the   term,   a   ' '  blistered ' '  boiler  plate,   and 
what  is  the  cause  thereof! 


Ans.  79.  A  blistered  boiler  plate  is  one  having  through  imperfect 
material,  blisters  on  its  surface.  This  is  caused  by  the  laminations  or 
layers  of  plate  separating,  the  outer  layer  becoming  burned  and  expanded 
by  heat,  forming  a  blister.  Sometimes  these  can  be  cut  away. 


Q.  81.  A  boiler  is  fitted  with  a  safety  valve  set  at  100  pounds,  and 
another  safety  valve  also  set  at  100  pounds  is  fitted  to  outlet  of  the  first  one. 
What  will  be  the  approximate  pressure  in  boiler  when  blowing  off  through 
both  valves? 

Ans.  81.  By  actual  experiments  it  has  been  found  that  the  pres- 
sures required  to  lift  each  valve  from  the  seat,  must  be  added  to  obtain 
the  pressure  in  the  boiler  when  blowing  through  both  valves,  hence,  in  this 
case,  the  pressure  in  the  boiler  would  be  approximately  200  pounds. 


Q.  84.  What  is  a  dead  weight  safety  valve!  What  are  its  advan- 
tages and  disadvantages? 

Ans.  84.  A  dead  weight  safety  valve  is  a  valve  loaded  with  weights 
acting  directly  on  the  valve.  The  weights  corresponding  with  the  total 
pressure  acting  on  the  valve.  For  example,  a  four-inch  valve  intended  to 
blow  at  100  pounds  per  square  inch  would  require  about  1,200  pounds  of 
weights.  This  type  of  valve  has  the  advantage  of  being  difficult  to  tam- 
per with,  as  the  adding  of  a  few  pounds  weight  woulfl  not  perceptibly 
change  the  blowing  point.  On  the  other  hand  they  are  heavy  and  cumber- 
some. 


Q.  85.     Explain    the    meaning    of    tensile    strength,    shearing    strength, 
and  torsional  strength. 

Ans.  85.     (a)     Tensile  strength  is  that  strength  in  a  substance  which 
resists  its  being  pulled  apart  lengthwise. 

(b)  Shearing  strength  is  the  strength  in  a  substance  which  resists  its 
being  cut  in  two,  as  with  a  pair  of  shears. 

(c)  Torsional   strength  is  the   strength  that   resists   twisting  strains, 
such  as  shafting  is  subjected  to. 


Q.  86.  Why  is  a  punched  rivet  hole  more  injurious  to  a  boiler  than  a 
drilled  hole? 

Ans.  86.  Forcing  a  punch  through  boiler  plates  strains  the  metal 
next  to  the  hole  so  punched,  and  starts  small  radial  cracks,  in  the  metal. 
If  the  hole  is  drilled  there  is  no  undue  disturbance  of  the  metal  hence  the 
plate  has  full  strength  right  up  to  the  edge  of  the  hole. 


Q.  87.  Is  there  any  advantage  in  machine  riveting  over  hand  rivet- 
ing— if  so,  what  does  it  consist  of? 

Ans.  87.  Machine  riveting  is  preferable  to  hand  riveting  because  the 
rivet  has  less  time  to  cool  before  the  head  is  fully  formed,  also  because 
pressure  is  exerted  on  the  rivet  while  hot,  enabling  it  to  entirely  fill  the 
hole  and  making  a  more  solid  joint  than  can  be  had  by  hand  work. 

21 


Pumps  and  Injectors. 


Q.  1.  If  both  are  run  under  throttled  steam,  would  a  8x6x10  steam 
pump  be  as  economical  as  a  10x6x10  pump  of  same  type;  the  conditions 
of  oneration  are  to  be  identical. 


of  operation  are  to  be  identical 


Ans.  1.  If  the  work  done  were  the  same  in  both  cases  the  smaller 
pump  would  be  the  more  economical.  If  the  work  done  were  proportional 
to  the  pump  dimensions  then  the  larger  would  have  the  advantage. 


Q.  2.  Given  a  centrifugal  pump  elevating  300  gallons  25  ft.  per  min- 
ute, what  change  in  power  used  would  occur  if  the  discharge  valve  be 
closed? 

Ans.  2.  There  would  be  a  large  drop  in  power  used  owing  to  the 
churning  or  whirling  of  the  water. 


Q.  3.  What  device  should  be  placed  in  the  suction  pipe  to  a  pump 
which  takes  its  supply  from  a  place  where  the  water  holds  sand  and  for- 
eign matter  in  suspension?  Describe  the  construction  of  such  a  device 
and  its  location. 

Ans.  3.  A  strainer  should  be  used  on  a  pump  suction  when  the  pump 
draws  its  supply  from  rivers  or  ponds  where  foreign  matter  is  held  in 
suspension.  A  strainer  consists  of  a  casting  screwed  on  the  end  of  the 
suction  pipe  in  the  shape  of  a  bowl.  Woven  wire  or  perforated  metal  is 
fastened  to  the  end  of  the  strainer  bowl.  The  fineness  of  the  mesh  is 
made  according  to  the  material  screened.  The  combined  area  of  the  open- 
ings to  be  three  or  four  times  the  area  of  the  pipe.  Where  the  end  of  the 
pipe  is  not  accessible  for  cleaning  a  strainer  is  placed  near  the  pump  on 
the  suction  pipe.  The  strainer  is  cast  iron  casting  in  *^e  shape  of  a  plug 
hat.  The  screen  is  fitted  to  the  casting  and  placed  so  that  the  water  has 
to  flow  through  it.  There  is  a  cap  placed  on  the  end  of  casting  for  clean- 
ing. 


Q.  58.  How  would  you  lengthen  or  shorten  the  stroke  of  a  duplex 
pump? 

Ans.  58.  The  stroke  of  a  duplex  pump  can  be  lengthened  by  increas- 
ing the  lost  motion.  To  shorten  the  stroke  the  lost  motion  should  be  de- 
creased. 


Q.  59.     What     is     the     advantage     and    disadvantage     of     an     outside 
packed  plunger  pump  as  compared  with  a  piston  pump! 

25 


Ans.  59.  An  outside  packed  plunger  pump  shows  at  a  glance  if  the 
packing  is  in  good  condition.  The  plungers  can  also  be  constructed  to 
better  withstand  heavy  pressures  than  ordinary  piston  pumps.  They  have 
the  disadvantage  of  taking  up  larger  floor  space,  and  great  friction  of 
packing  around  plungers. 


Q.  60.  Should  a  pump,  pumping  hot  water  and  receiving  it  at  atmos- 
pheric pressure  be  placed  above  or  below  the  source  of  supply  f  Whyf 

Ans.  60.  The  pump  should  be  placed  below  its  source  of  supply,  so 
that  the  water  may  flow  by  gravity  into  the  pump.  The  vapor  arising 
from  the  hot  water  would  destroy  the  partial  vacuum  necessary  to  raise 
the  water,  if  the  pump  was  placed  above  its  source  of  supply. 


Q.  61.  How  does  a  plunger  or  piston  pump,  setting  above  its  source 
of  supply,  draw  the  water  and  deliver  it  out  of  discharge  pipe? 

Ans.  61.  When  a  pump  raises  water  it  is  owing  to  the  fact  that  a 
vacuum  has  been  created  in  the  pump  and  suction  pipe,  the  pump-piston 
or  plunger  having  expelled  the  air  out  of  the  same.  The  atmospheric 
pressure  acting  upon  the  water  supply  has  a  tendency  to  destroy  this 
vacuum  by  equalizing  {he  pressures.  It  will,  therefore,  endeavor  to  do 
this  by  entering  the  suction  inlet,  but  the  end  of  the  suction  being  im- 
mersed in  the  water,  the  water  will  be  forced  up  into  the  suction  pipe  in- 
stead until  it  reaches  the  pump,  entering  same  through  the  suction  valves, 
being  expelled  through  the  discharge  valves  into  the  discharge  pipe. 
Should  the  partial  vacuum  maintained  by  the  pump  in  the  suction  pipe 
become  equalized  with  the  atmospheric  pressure  at  a  point  below  the  pump, 
the  water  will  only  rise  to  this  point  and  the  pump  will  not  be  able  to  get 
water  until  this  vacuum  has  been  sufficiently  increased. 


Q.  62.     What  limits  the  height  a  pump  can  be  placed  above  its  source 
of   supply? 

Ans.  62.  The  atmospheric  pressure  limits  the  height  a  pump  can  be 
placed  above  its  source  of  supply.  Theoretically,  this  is  about  34  feet, 
but  it  requires  the  forming  of  a  perfect  vacuum  in  order  to  obtain  this 
result.  To  raise  the  water  some  26  or  27  feet  requires  the  pump  to  re- 
duce the  atmospheric  pressure  in  the  suction  pipe  about  12  pounds,  or,  in 
other  words,  the  pump  has  to  maintain  a  vacuum  in  the  suction  pipe  of 
some  24  inches.  Pumps  doing  this  can  be  considered  as  giving  good  re- 
sults. 


Q.  63.  Under  what  condition  is  an  air-chamber  on  the  suction  pipe 
most  beneficial  in  obtaining  good  results? 

Ans.  63.  Air  or  vacuum  chambers  on  the  suction  pipe  are  of  most 
benefit  on  pumps  with  a  high  or  long  lift.  A  vacuum  chamber,  owing  to 
the  compression  and  expansion  of  the  air  contained  therein,  facilitates 
changing  a  continuous  into  intermittent  motion.  The  water  in  suction 
coming  to  a  standstill  upon  the  end  of  stroke  is  brought  to  rest  gradu- 
ally by  the  compression  of  the  air  in  vacuum  chamber,  when  the  next 
stroke  commences  the  air  expands  and  helps  the  piston  starting  the  water 
in  motion  again.  Pumps  running  at  a  high  rate  of  speed  should  be  fitted 
with  vacuum  chambers,  as  it  allows  them  to  run  with  less  noise  and  tends 
to  ease  the  strain  on  the  moving  parts  of  the  pump. 

26 


Q.  64.  What  is  the  object  of  an  air-chamber  on  the  discharge  of  a 
pump? 

Ans.  64.  The  air  chamber,  due  to  the  compression  and  expansion  of 
the  air  contained  therein,  causes  a  steady  discharge  of  water.  During  the 
time  the  piston  makes  a  stroke  the  air  is  compressed,  expanding  as  the 
piston  comes  to  rest,  acting  as  a  cushion  and  gradually  reducing  the  flow 
of  water  until  the  beginning  of  the  next  stroke.  It  also  allows  the 
valves  to  seat  more  easily. 


Q.  65.     What  is  the  object  of  a  foot  valve  on  the  suction  pipe? 

Ans.  65.  It  keeps  the  suction  pipe  full  of  water  and  greatly  assists 
the  pump  in  case  of  high  lifts  or  leaky  valves.  Suction  pipes  exposed  to 
freezing  temperature  should,  if  fitted  with  foot  valves,  have  some  means  of 
draining  water  out  of  suction  pipe  when  shutting  down  any  length  of 
time. 


Q.  66.  What  is  the  best  method  of  setting  steam  valves  on  a  du- 
plex pump? 

Ans.  66.  Place  both  pistons  in  center  of  travel;  the  rocker  arms 
will  then  be  plumb.  Kemove  steam  chest  cover  and  set  steam  valves 
in  central  position  over  steam  ports,  and  adjust  all  lost  motion  equally 
on  each  side  of  collars  or  nuts  which  move  the  valves.  Before  closing 
steam  chest  one  steam  valve  should  be  moved  so  as  to  open  steam  port; 
this  will  facilitate  starting  up. 


Q.  67.     Why  has  the  steam  valve  of  a   duplex  pump  no  lap? 

Ans.  67.     The  valves  have   no  lap,   as  the   pump  must  take  steam   the 
full  stroke. 


Q.  68.  Why  is  it  necessary  for  a  steam  pump  to  have  steam  admis- 
sion the  full  length  of  stroke? 

Ans.  68.  A  steam  pump  having  no  balance  wheel  or  other  means  of 
momentum  would  stop  if  steam  were  cut  off  at  partial  stroke,  due  to  the 
steam  pressure  falling  after  cutting  off  steam  supply,  and  the  resist- 
ance would  soon  equal  and  exceed  the  moving  force. 


Q.  69.     What    is    the    material    best    suited    for    the    construction    of 
pump   valves  handling:  — 

(a)  Cold  water. 

(b)  Hot  water. 

(c)  Compressed    air. 

Ans.  69     (a)     Pumps   handling    cold  water   should   have   pure   rubber 
valves. 

(b)  Pumps   handling  hot   water  should   be   fitted   with   either  vulcan- 
ized rubber  valves  or  valves  made  of  composition  metal. 

(c)  Pumps  compressing  air  give  best  results  with  steel  valves. 

27 


Q.  70.  What  is  the  object  of  lost  motion  in  the  steam  valve  gear  of 
a  pump? 

Ans.  70.  The  lost  motion  allows  the  valve  to  be  motionless  part 
of  the  stroke,  thereby  permitting  the  piston  to  make  the  full  stroke  be- 
fore the  valve  is  reversed. 


Q.  71.  What  is  the  object  of  a  cushion  valve  on  steam  end  of  a 
pumpf 

Ans.  71.  Cushion  valves  are  used  for  the  purpose  of  regulating  the 
degree  of  cushion  at  the  end  of  stroke.  It  connects  the  steam  and  exhaust 
ports.  Closed,  it  gives  the  greatest  amount  of  cushion.  By  opening  the 
cushion  valve  a  little  at  a  time,  the  amount  of  cushion  required  can  be 
easily  determined. 


Q.  72.     How  is  a  centrifugal  pump  constructed? 

Ans.  72.  The  moving  part  of  a  centrifugal  pump  consists  of  a  shaft, 
having  wings  or  arms  radiating  from  the  same,  usually  curved  in  a  di- 
rection opposite  from  the  direction  of  rotation.  The  whole  is  enclosed  in 
a  case,  the  case  having  openings  in  the  center  around  the  shaft  and  an 
opening  at  a  point  farthest  from  the  shaft.  The  center  openings  are 
for  the  suction,  the  other  opening  is  for  the  discharge. 


Q.  73.  How  does  a  centrifugal  pump  work,  and  what  work  is  it  best 
adapted  for? 

Ans.  73.  The  shaft  and  arms  rotating  in  the  pump  case  impart 
motion  to  whatever  substance  is  contained  in  the  same,  throwing  it  out- 
ward from  the  center  by  centrifugal  force,  expelling  it  out  of  discharge 
opening  at  the  outer  rim  of  the  pump  case.  In  this  manner  a  vacuum  is 
formed  in  the  pump  and  suction  pipe,  allowing  the  water,  or  other  sub- 
stance pumped,  to  enter  the  pump  to  be  in  turn  expelled  out  of  discharge. 
These  pumps  must  be  primed  when  standing  above  their  supply;  this  is 
sometimes  accomplished  by  shutting  the  discharge  and  having  a  pump 
or  ejector  expel  all  air  contained  in  suction  pipe  and  pump  case,  start- 
ing the  pump  and  opening  discharge  valve  when  all  air  is  expelled.  These 
pumps  are  extensively  used  for  handling  large  volumes  of  water  quickly, 
such  as  in  the  case  in  tanneries,  paper  mills,  dry  docks,  etc.,  as  they  are 
valveless,  sand,  gravel  and  other  impurities  have  no  effect  upon  their 
operation. 


Q.  74.  How  is  a  rotary  pump  constructed,  and  what  are  the  prin- 
ciples governing  its  operation? 

Ans.  74.  A  rotary  pump  is  constructed  of  casing  enclosing  P  piston 
or  pistons,  sometimes  called  impellers.  They  are  made  several  ways. 
Some  have  the  butments  movable,  while  others  have  a  movable  wing  on 
the  pistons  which  slides  in  and  out  when  passing  the  butments.  One 
type  is  made  with  two  gear-like  impellers  running  together,  others  with 
impellers  that  are  larger  top  and  bottom,  and  set  so  that  the  larger  part 
of  one  fits  into  the  smaller  part  of  the  other;  each  impeiier  is  mounted 
on  separate  shafts  which  are  connected  by  gears. 

28 


The  principle  governing  the  action  is  as  follows:  Running  at  a  high 
rate  of  speed  the  impellers  create  a  partial  vacuum,  into  which  the  atmos- 
pheric pressure  forces  the  water.  The  construction  is  such  that  the  water 
once  caught  by  the  impellers  is  prevented  from  returning  to  the  suction 
side  and  is  forced  into  the  discharge  pipe. 


Q.  76.  Why  is  an  auxiliary  steam  valve  necessary  on  all  single  cylin- 
der steam  pumps? 

Ans.  76.  An  auxiliary  valve  is  necessary  to  operate  the  main  valve 
of  the  pump.  If  the  main  valve  of  the  pump  was  mechanically  con- 
nected to  piston  rod  of  pump,  the  steamport  would  be  covered  slowly 
toward  the  end  of  stroke  and  the  stroke  would  not  be  completed,  there- 
fore the  valve  would  not  reverse. 


Q.  82.  Is  a  belt  or  motor  driven  boiler  feed  pump  more  economical  than 
a  direct  acting  steam  pump  I  If  so,  why? 

Ans.  82.  A  belt  or  motor  driven  pump  is  more  economical  than  a  direct 
acting  steam  pump,  because  the  power  to  operate  it  is  usually  taken  from  an 
engine  using  steam  expansively. 


Q.  83.     About  what  efficiency  should  be  obtained  from  an  injector. 

Ans.  83.  The  injector,  taken  as  a  pump,  has  a  very  low  efficiency,  much 
below  that  of  the  ordinary  direct  acting  steam  pump.  Considered  as  a  pump 
and  feed  water  heater,  it  has  an  efficiency  of  nearly  100  per  cent. 


Q.  84.     How  is  the  steam  used  in  an  injector  utilized? 

Ans.  84.  The  steam  condensed  in  the  operation  of  the  injector  is  used 
in  heating  the  feed  water  and  forcing  it  into  the  boiler.  The  construction 
of  the  injector  is  such  that  when  steam  from  the  boiler  is  admitted  to  it  a 
vacuum  is  created  in  the  suction  pipe,  causing  the  water  to  flow  through 
the  injector.  The  steam  is  condensed  and  its  velocity  imparted  to  the  water, 
thus  giving  the  water  sufficient  velocity  to  force  it  into  the  boiler. 


Q.  85.  Why  does  an  injector  refuse  to  operate  when  the  feed  water  is 
too  hot? 

Ans.  85.  As  there  is  no  means  of  exhausting  the  steam  from  an  injector 
except  by  condensing  it  and  putting  it  into  the  boiler  along  with  the  feed 
water,  it  follows  that  enough  water  must  enter  the  injector  to  condense  the 
steam ;  and  if  the  water  is  too  hot,  enough  of  it  cannot  enter  the  injector  to 
condense  the  steam,  hence  the  injector  will  not  work. 


Q.  86.  How  can  a  feed  water  heater  be  used  in  conjunction  with  an  in- 
jector? 

Ans.  86.  The  water  from  an  injector  may  be  passed  through  a  closed 
feed  water  heater  before  entering  the  boiler.  An  open  feed  water  heater  can- 
not be  used  in  conjunction  with  an  injector  if  the  feed  water  is  heated  to  a 
perceptible  degree. 


Q.  87.  Explain  fully,  and  in  plain  language,  how  an  injector  forces 
water  into  the  boiler  from  which  it  receives  its  steam  supply. 

Ans.  87.  To  feed  water  into  a  steam  boiler  by  means  of  an  injector  is 
mainly  accomplished  by  the  existing  difference  in  velocity  between  the  steam 
and  the  water  flowing  from  the  boiler  under  the  same  pressure.  The  ratio 
between  the  two  velocities  is  quite  large,  leaving  considerable  energy  for 
forcing  fresh  water  into  the  boiler.  The  mass  of  steam  which  meets  the 
comparatively  cold  feed  water  in  the  vacuum  chamber  of  the  injector  acts 
upon  the  latter  by  impact  of  the  condensed  water  upon  the  feed  water. 
Usually  the  ratio  between  the  two  masses  (steam  and  feed  water)  is  1  to  10 
or  1  to  13  and  the  velocity  with  which  the  water  is  forced  into  the  boiler  is 
at  least  as  many  times  less  than  the  steam  velocity  as  the  feed  water  mass 
weighs  more  than  the  condensed  steam  mass,  which  forces  the  combined  mass 
into  the  boiler.  For  illustration,  the  following  example  may  be  given: 

Assuming  the  boiler  pressure  to  be  75  pounds  gauge  pressure,  then  the 
velocity  with  which  the  water  would  flow  out  of  the  boiler  would  be 


V2X  32.2X75X2.31  =105  feet  per  second. 

The  velocity  with  which  the  steam  would  flow  from  the  boiler  would  de- 
pend on  the  fall  of  temperature  of  the  steam,  which  would  be  from  320  to 
212°  F  and  velocity  would  be  (steam  considered  dry), 


V778X2X32.2X(320— 212)=2532  feet  per  second. 

Assuming  now  that  one  pound  of  steam  delivers  10  pounds  of  water  into 
the  boiler,  making  a  total  of  11  pounds,  then  the  steam  velocity  is  thus  re- 

2532 

duced  from  2532  feet  to  =230  feet  per  second,  and  if  25%  friction  is 

11 

produced  in  the  water  passage  then  the  water  will  still  be  forced  into  the 
boiler  with 

230 X. 75 — 105=67  feet  per  second. 


Heaters  and  Condensers. 


Q.  37.  What  is  the  difference  in  construction  between  the  open  and  the 
closed  types  of  feed  water  heaters?  Describe  how  the  feed  water  is  heated 
in  each  type? 

Ans.  37.  In  an  open  feed  water  heater  the  steam  and  water  come  in 
actual  contact  with  each  other,  the  steam  thereby  heating  the  water.  The 
feed  water  sometimes  enters  this  type  of  heater  in  the  form  of  a  spray,  and 
also  quite  often  by  filling  a  series  of  pans,  overflowing  them  and  tending  to 
purify  the  water  thereby.  In  a  closed  heater  the  feed  water  does  not  come 
in  actual  contact  with  the  steam,  but  is  heated  by  being  passed  through  a 
series  of  tubes  or  a  coiled  tube,  the  steam  enveloping  these  tubes  or  tube, 
heating  the  water. 


Q.  38.     What  is  a  superheater? 

Ans.  38.  A  superheater  is  an  arrangement,  usually  of  pipes,  placed  in 
the  combustion  space  of  the  furnace,  or  in  the  uptake.  The  steam  on  its  way 
from  the  boiler  to  the  engine  passes  through  this  superheater  and  is  super- 
heated. 


Q.  39.     Describe  the  construction  of  a  fuel  economizer. 

Ans.  39.  A  fuel  economizer  is  an  arrangement  of  tubes  placed  in  the 
uptake  of  a  boiler  or  battery  of  boilers,  through  which  the  feed  water  passes 
on  its  way  to  the  boilers;  the  flue  gases  heating  the  feed  water  while  pass- 
ing through  these  tubes. 


Q.  40.  Describe  constructional  details  of  the  most  approved  type  of 
condensers,  of  both  jet  and  surface  type,  with  reasons  why  each  type  is  pe- 
culiarly adaptable  for  some  classes  of  service  and  not  for  others. 

Ans.  40.  The  surface  condenser  consists  of  a  number  of  brass  tubes 
within  a  box  or  case.  Tubes  should  be  well  tinned,  and  should  be  small  as 
possible  for  good  distribution  of  the  condensing  water.  It  should  be  pro- 
vided with  a  good  circulating  pump  to  force  the  water  rapidly  around  the 
condensing  surfaces,  and  also  be  provided  with  an  air  pump  to  remove  air 
and  vapor.  This  form  of  a  condenser  is  used  where  the  water  is  salty  or 
very  impure  as  the  steam  does  not  come  in  direct  contact  with  condensing 
water  and  condensed  steam  can  be  used  for  boiler  feed  water,  and  adapted 
for  marine  purposes. 

A  jet  condenser  consists  of  a  box  or  case  in  which  the  exhaust  steam 
comes  in  contact  with  condensing  water  in  form  of  a  spray  falling  on  a 
scattering  plate.  The  pump  should  be  placed  below  the  condenser  for  re- 
moving the  air  and  water.  This  form  of  condenser  takes  less  water  and 
costs  less  to  install. 

31 


Q.  41.  How  many  square  feet  of  Tooling  surface  should  be  required  in  a 
surface  condenser  for  an  engine  developing  250  I.  H.  P.  and  using  23  Ibs.  of 
steam  per  I.  H.  P.  per  hour? 

Ans.  41.  Several  authorities  give  the  constant  .0944  multiplied  by  the 
pounds  of  steam  per  horse  power  hour  as  the  number  of  square  feet  of  cool- 
ing surface  required.  In  this  instance  it  will  be  542  square  feet. 


Q.  42.  How  many  gallons  of  water  would  be  needed  per  hour  to  con- 
dense the  steam  from  an  engine  running  under  conditions  as  mentioned  in 
No.  41?  Pressure  of  exhaust,  4  Ibs.  absolute.  Temperature  of  steam  at 
condenser  is  170°,  cooling  water  entering  at  60°  and  leaving  at  112°. 

Ans.  42.  13,150  gallons.  This  answer  is  obtained  by  use  of  the  follow- 
ing rule : 

1128.64—170+32 

—  =19.05X250X23—8.33 

112—60 


Q.  43.  About  how  much  more  cooling  water  is  required  in  a  surface  con- 
denser than  a  jet  condenser? 

Ans.  43.  It  takes  about  25  to  35%  more  water  for  surface  condensers 
than  for  those  of  the  jet  type.  This  is  due  to  the  water  not  coming  in  direct 
contact  with  the  steam  in  the  surface  type  of  condenser. 


Q.  44.  In  starting  up  a  jet  condensing  engine,  which  would  you  start 
first,  the  engine  or  condenser,  assuming  them  to  work  independently;  and 
which  would  you  shut  down  first?  We  will  assume  there  are  no  pockets  for 
water  between  condenser  and  engine. 

Ans.  44.  Start  the  condenser  before  starting  engine,  and  shut  down  the 
engine  before  shutting  down  the  condenser. 


Q.  45.  (a)  What  is  a  vacuum  breaker  and  why  are  they  used?  (b) 
Is  vacuum  a  power? 

Ans.  45.  (a)  A  vacuum  breaker  is  a  valve  attached  to  the  condensing 
chamber  of  a  condenser,  or  to  the  exhaust  pipe  leadfng  to  the  condenser.  It 
may  be  arranged  to  be  automatic  in  action,  or  not,  as  may  be  desired.  It 
admits  air  to  break  or  destroy  the  vacuum. 

(b)  Vacuum  is  not  power,  as  all  power  in  a  steam  engine  is  derived  from 
the  pressure  of  steam  on  the  piston ;  if  there  is  no  resistance  on  one  side  of 
the  piston  the  entire  pressure  is  available  on  the  other  side  of  the  piston. 


Q.  46.  The  temperature  of  water  in  hot  well  being  more  than  212°  and 
you  lose  your  vacuum,  what  would  be  the  cause? 

Ans.  46.  With  a  temperature  of  212°  in  the  hot  well  sufficient  vapor  will 
be  present  to  destroy  all  vacuum,  and  under  such  conditions  a  vacuum  is  not 
possible. 


Q.  47.     What  are  the  necessary  cocks  and  valves  in  an  engine  room  of  a 
idensing  engine? 


condensing  engine? 


Ans.  47.  Throttle  valve  of  engine,  valve  in  exhaust  pipe  between  engine 
and  condenser,  throttle  valve  for  steam  end  of  condenser  pump,  atmospheric 
valve  in  exhaust  pipe  line,  valve  for  priming  condenser,  suction  valve  on 
suction  pipe  to  condenser,  and  cocks  on  the  steam  pump  cylinder  of  con- 
denser. 


Q.  48.  What  is  the  method  used  in  cleaning  the  external  surface  of  fuel 
economizer  tubes? 

Ans.  48.  The  fuel  economizer  is  provided  with  a  set  of  scrapers  en- 
circling the  tubes  which  are  alternately  raised  and  lowered  the  entire  length 
of  the  tube  by  mechanical  means. 


.     Q.  49.     Under  what  circumstances  is  the  open  type  of  feed  water  heater 
preferable  to  a  closed  type  of  feed  water  heater? 

Ans.  49.  Where  pumps  are  used  instead  of  injector,  when  the  feed  water 
is  full  of  scale  forming  matter,  and  where  there  are  a  lot  of  drips  to  be  taken 
back  into  the  feed  water. 


Furnaces,  Chimneys,   Draft,    Fuels,   Com- 
bustion, Etc. 


Q.  1     What  conditions  must  exist  in  the  furnace  of  a  steam  boiler  to  in- 
sure practically  complete  combustion? 

Ans.  1.     Must  have  a  high  temperature  and  the  proper  amount  of  air 
brought  into  intimate  contact  with  the  fuel  and  distilled  gases  from  same. 


Q.  2.  With  coal  at  $2.25  per  ton  (of  2,000  Ibs.)  and  an  actual  evapora- 
tion of  7.5  Ibs.— show  by  a  short  metnod  the  cost  of  1,000  Ibs.  of  steam ;  also 
how  many  Ibs.  can  be  evaporated  for  one  dollar? 

Ans.  2.  To  find  the  cost  per  1,000  Ibs.  of  water  evaporated  where  the 
cost  per  ton  of  coal  and  the  evaporation  are  given :  Divide  the  cost  per  ton 
of  coal  by  twice  the  evaporation  gives  cost  per  1,000  Ibs.  6666.6  Ibs.  of 
water  for  $1.00,  or  15  cts.  per  1,000  Ibs. 


Q.  3.  In  a  combined  steam  boiler  and  coal  burning  furnace,  why,  in 
practice,  is  it  impossible  to  realize  90%  efficiency? 

Ans.  3.  Assume  a  coal  with  13,000  B.  T.  U.  in  it.  Deduct  5%  loss  for 
ashes  and  5%  loss  for  radiation  there  is  lost  in  these  two  ways  10%.  In 
addition  to  these  and  some  other  small  losses  we  have  to  heat  20  Ibs.  of  air 
to  each  Ib.  of  fuel  and  if  the  specific  heat  of  the  gases  is  .25  there  is  lost  five 
heat  units  for  each  degree  raise  in  temperature  of  the  gases  between  enter- 
ing and  leaving  the  furnace.  If  this  raise  is  500  degrees  we  thus  lose  500 
times  5  or  2,500  heat  units  or  19%  about  on  this  account  alone,  makine  a 
total  for  these  three  causes  almost  30%.  Hence  it  is  impossible  in  practice 
to  realize  90%  efficiency  in  a  boiler  furnace.  • 


Q.  4.     In  a  typical  mechanical  draft  plant,  what  percentage  of  the  power 
generated  should,  in  good  practice,  be  required  to  produce  the  draft? 

Ans.  4.     From  3% 


Q.  43.  How  should  chimney  flues  and  feed  water  mains  be  arranged 
when  fuel  economizers  are  used? 

Ans.  43.  Chimney  flues  and  feed  water  mains  should  be  arranged  with 
by-pass  flues  and  mains  so  that  the  economizer  can  be  cut  out  whenever  it 
becomes  necessary  to  do  so. 


Q.  44.     How  does  the  use  of  an  economizer  affect  the  chimney  draft; 
also  the  foreign  matter  contained  in  the  feed  water? 

Ans.  44.     Economizers  reduce  the  temperature  of  the  gases  passing  up 
the  chimney,  hence  it  reduces  the  intensity  of  the  draft. 

Heating  the  feed  water  causes  foreign  matter  held  in  suspension  to  de- 
posit, and  as  the  heating  takes  place  in  the  economizer  the  deposit  will  be 
there. 


Q.  85.  Describe  in  a  general  way  the  construction  of  an  automatic 
damper  regulator,  and  the  principles  governing  its  operation. 

Ans.  85.  Describing  damper  regulators  in  a  general  way,  it  may  be 
said  that  two  distinct  types  cover  the  field  of  general  use.  First,  is  the  low 
pressure  regulator,  where  the  steam  pressure  acts  directly  on  a  diaphragm, 
which  by  a  system  of  levers  controls  the  damper  or  dampers.  This  type  is 
extensively  used  for  low  pressure  heating  plants. 

Then  comes  the  high  pressure  type  of  regulator,  where  the  steam  acts  on 
a  diaphragm  or  piston  counterbalanced  by  weights.  This  controls  a  valve 
which  in  turn  admits  water  under  pressure  to  a  piston  which  actuates  the 
damper.  The  water  pressure  may  be  taken  from  the  boiler  or  other  suitable 
source. 


Q.  89.  Should  there  be  a  difference  in  the  size  of  a  fan  supplying  me- 
chanical draft  to  a  boiler  under  the  following  conditions: 

(a)  Forced  draft. 

(b)  Induced  draft. 

Ans.  89.  Owing  to  the  fact  that  air  after  having  passed  through  the  fur- 
nace has  expanded  in  volume,  a  fan  supplying  cold  air  to  the  bottom  of  the 
grates  can  be  smaller  than  a  fan  placed  in  the  uptake  of  a  boiler,  the  duty 
in  both  cases  being  alike  in  reference  to  work  being  done  by  the  boiler. 

The  first  Would  supply  a  forced  draft,  while  the  second  would  induce  a 


draft  by  exhausting  the  air  from  the  uptake. 
As  the  larger  fan 


handles  air  which  is  of  a  lesser  density,  owing  to  its 

volume  being  expanded,  the  power  required  to  drive  it  would  not  materially 
differ  from  that  necessary  to  operate  the  fan  handling  the  cold  air. 


Air  Compressors. 


Q.  5.  State  what  advantages  there  are  in  using  an  air  lift  for  deep  well 
service,  over  those  to  be  obtained  by  use  of  deep  well  pumps ;  also  conditions 
under  which  the  best  results  may  be  attained  by  use  of  the  latter? 

Ans.  5.  The  advantage  of  an  air  lift  over  a  deep  well  pump  for  deep 
well  service,  is  its  simplicity,  being  able  to  concentrate  all  the  machinery 
in  one  place  which  can  be  conveniently  located,  and  its  ability  to  handle 
water  containing  grit  without  injury  to  the  machinery,  but  where  the  wells 
are  not  scattered  and  water  is  pure  the  deep  well  pump  has  a  greater  ef- 
ficiency. 


Q.  8.  What  is  the  difference  between  the  real  and  apparent  clearance 
in  an  air  compressor;  how  can  the  real  clearance  best  be  determined? 

Ans.  8.  The  apparent  clearance  in  an  air  compressor  is  the  space  left, 
which  is  not  swept  through  by  the  piston  and  is  usually  very  small,  i.  e.,  sel- 
dom more  than  %  but  frequently  less  than  1/16  of  an  inch  between  piston 
and  cylinder  head.  The  real  clearance  is  the  amount  of  space  the  compressed 
air,  that  is  left  in  the  compressor  after  completion  of  stroke,  will  occupy 
after  it  is  re-expanded  to  the  original  suction  pressure.  This  clearance  can 
best  be  determined  on  the  compressor  indicator  diagram  and  is  that  part  of 
the  stroke  where  the  expansion  line  meets  the  suction  pressure  line,  or  in 
other  words,  where  the  prevailing  pressure  in  the  compressor  during  the  re- 
turn stroke  reaches  the  suction  pressure. 


Q.  14.  Given  an  air  compressor  with  a  cylinder  12  inches  long,  tak- 
ing free  air  at  atmospheric  pressure  (14.7  Ibs.),  and  discharging  against 
a  pressure  of  100  pounds  gauge  pressure;  considered  adiabatically,  what 
will  be  pressures  at  3d,  6th  and  9th  inches  of  the  stroke,  and  at  what  por- 
tion of  the  stroke  (considered  in  inches)  will  the  discharge  of  air  com- 
mence? 

Ans.  14.     If  P,=absolute  final  air  pressure, 
P  ^absolute  initial  air  pressure, 
Vt  =  final  volume  of  air, 
V  =initial  volume  of  air, 
then 

P,       f  V   I  1.41 

and 
P  V, 


V  P,    I  0.71 

V,       I    P 

36 


hence  the  pressures  at  the  3d,  6th  and  9th  inches  are  20.8,  55.3  and  98 
pounds  absolute,  respectively,  and  the  final  volume  at  100  pounds  gauge 
pressure  would  be  2.788  inches  from  the  end  or  76.8%  of  the  entire  stroke. 


Q.  23.  With  a  condensing,  steam  driven  air  compressor  using  15  pounds 
of  steam  per  horse  power,  and  compressing  5  cubic  feet  of  free  air  for  each 
horse  power  exerted,  how  many  degrees  can  the  feed  water  be  heated  by  the 
compressed  air,  if  the  latter  gives  up  300  degrees  of  its  temperature, 
ignoring  all  losses? 

Ans.  23.  Assuming  the  temperature  of  the  air  when  entering  com- 
pressor to  be  60°  F.  then  5  cu.  ft.  would  weigh  .3805  of  a  pound.  The 
specific  heat  of  air  is  .2375.  hence  the  heat  given  off  by  5  cu.  ft.  of  air  if 
reduced  300°  F.  is  . 3805 X. 2375X300=27  B.  T.  U.,  and  since  15  pounds  of 
water  must  at  least  be  fed  to  the  boiler  for  every  5  cu.  ft.  of  air  compressed, 
it  follows  that  the  temperature  the  feed  water  can  be  raised  amounts  to  only 
27 

—=1.8°  F. 
15 


Mechanics,   Piping,  Refrigeration,  Test 
Apparatus,  Steam,  Elevators,  Gas  Pro- 
ducers, Etc.,  and  Miscellaneous. 


Q.  1.  What  features  should  be  embodied  in  the  design  of  gas  engines  of 
100  h.  p.  for  use  in  driving  a  mixed  motor  and  lighting  load?  Peak  load  to 
be  of  short  duration  at  10  per  cent,  overload,  and  normal  load  of  about 
75  h,  p. 

Ans.  1.  The  features  that  should  be  embodied  in  the  design  of  gas  en- 
gine should  be  the  ' '  Throttling  Governor, ' '  very  sensitive,  heavy  fly  wheel, 
(3  or  4)  three  or  four  cylinder,  (4)  four  cycle. 


Q.  2.  Describe  the  construction  and  operation  of  some  one  type  of  suc- 
tion gas  producer. 

Ans.  2.  A  suction  gas  producer  has  the  following  parts:  A  generator, 
smoke  pipe  evaporator,  scrubber,  and  gas  receiver.  The  generator  is  an  or- 
dinary cylindrical  stove  lined  with  fire  brick  in  which  the  coal  burns.  The 
evaporator  containing  water  is  placed  inside  of  the  steel  shell  of  the  pro- 
ducer or  generator  in  contact  with  the  fire  and  generates  steam  which  is  con- 
ducted through  a  pipe  and  discharged  beneath  the  grate  mixing  with  the 
air  as  it  is  drawn  up  into  the  fire.  The  heat  of  the  fire  decomposes  this 
steam  into  its  constituent  parts  of  oxygen  and  hydrogen.  The  hydrogen 
increases  the  heating  value  of  the  fuel  20  to  25  heat  units  per  foot.  The 
second  large  vessel  is  what  is  known  as  the  scrubber.  This  is  a  boiler  iron 
cylinder  filled  with  coke.  The  gas  from  the  producer  enters  this  scrubber 
at  the  bottom,  passing  upward  to  the  pipe  leading  to  the  gas  receiver  or  en- 
gine. At  the  top  of  this  scrubber  a  water  pipe  enters  and  water  is  sprayed 
on  top  of  the  coke  and  runs  down  through  the  coke  to  the  trap  at  the  bot- 
tom. This  cools  the  gas  and  washes  out  the  dust  and  other  impurities,  which 
are  drawn  through  the  producer  by  the  suction  of  the  engine.  The  gas  re- 
ceiver is  a  small  storage  tank  for  gas.  To  start  the  producer  a  fire  is  kindled 
on  the  grate.  The  vent  in  the  smoke  pipe  is  opened  to  the  outer  air.  The 
blower  is  started,  taking  from  15  to  30  minutes  the  first  time  that  the  pro- 
ducer is  started.  The  fan  must  be  operated  until  the  test  flame  burns  with 
a  bright  blue  flame.  Then  shut  the  damper  in  the  smokestack.  The  blower 
is  stopped  and  the  valve  to  the  gas  receiver  is  opened.  The  engine  is  then 
started. 


Q.  3.  Given  the  famous  Ferris  wheel,  250  feet  in  diameter:  A  band  or 
tire  of  steel  is  made  for  same,  and  found  to  be  12  inches  too  long.  How 
much  larger  in  diameter  is  the  band  than  the  diameter  of  the  wheel;  and 


how  many  degrees  Fahr.  drop  in  temperature  will  be  needed  to  shrink  the 
band  so  that  it  will  fit  the  wheel,  if  the  coefficient  of  expansion  is  .00000686? 


Ans.  3.  1 

— =185°  Fab. 
(250X3.1416+1)  X.00000686 


Q.  4.     How  wide  should  a  double  belt  be  to  transmit  500  h.  p.  from  a 
drive  wheel  22  ft.  in  diameter  running  65  r.  p.  m.f 

600X500 
Ans.  4.     78  ins.  wide,  —  — .     Single  belt,  7/10  of  that  trans- 

22X3.1416X65 
mitted  bv  a  double  belt. 


Q.  5.  If  the  power,  as  given  in  No.  4  was  to  be  transmitted  from  shaft 
.to  shaft,  which  would  require  the  heavier  belt;  in  one  case  the  driving  and 
receiving  pulleys  are  both  48  inches  in  diameter,  and  in  the  other  case  the 
diameters  are  72  inches? 

Ans.  5.  The  belt  on  the  48"  pulleys  would  have  to  be  2/3  wider  than  the 
one  on  the  72"  pulleys  as  the  speed  in  feet  per  minute  is  more. 


Q.  6.  What  type  of  passenger  elevator  best  meets  the  requirements  of 
office  building  service,  it  being  assumed  that  the  lift  is  not  over  200  ft.  nor 
the  car  travel  over  350  ft.  per  minute?  Explain  in  detail. 

Ans.  6.  Electric  type  elevator  when  continued  service  can  be  had  or  ob- 
tained. (Eeasons.)  No  expense  when  elevator  not  in  use.  Easy  to  operate 
and  when  properly  constructed  cost  of  maintenance  very  light. 


Q.  7.  What  is  the  smallest  size  elevator  installation  in  which  it  would 
be  a  paying  investment  to  install  a  high  duty  pumping  engine,  one  that 
would  develop  a  horse  power  on  not  more  than  35  pounds  of  steam  per  hour? 

Ans.  7.  Two  (2)  two-ton  elevators  running  continuously  not  less  than 
150  lift  and  speed  not  less  than  150  feet  per  minute. 


Q.  8.     Assuming  a  high  pressure,  inverted  hydraulic  elevator;  does  it  use 
more  power  running  light  or  loaded? 

Ans.  8.     The  same  amount  is  used  under  both  conditions  as  the  cylinder 
must  be  filled  in  either  case. 


Q.  9.  WThat  features  of  design  and  construction  should  be  embodied  in 
valves,  of  either  the  globe  or  gate  types,  for  use  on  high  pressure  steam 
lines,  where  the  service  must  be  continuous? 

Ans.  9.  All  high  pressure  valves  should  be  constructed  heavy  enough  to 
withstand  all  strains,  and  those  of  6"  or  over  should  have  flange  connections 
and  by-pass  also  be  constructed  so  valve  stem  could  be  packed  when  valve  is 
open. 

39 


Q.  10.     In  locating  standpipes  for  fire  protection  purposes,  in  mills  or 
office  buildings,  which  is  preferable,  the  inside  or  outside  pipes,  and  why? 

Ans.  10.     Standpipe  should  be  placed  on  the  outside  for  easy  access. 


Q.  11.  What  should  the  position  of  a  globe  valve  be  placed  on  pipes 
lying  in  a  horizontal  position? 

Ans.  11.  A  globe  valve  placed  in  a  horizontal  pipe  line  should  have  its 
stem  in  a  horizontal  position.  When  so  placed  it  prevents  the  trapping  of 
water  in  the  pipe;  the  valve  seat  will  be  in  a  vertical  position,  and  as  it  is 
nearly  the  full  size  of  the  pipe  it  allows  complete  drainage.  Should  the  stem 
be  in  a  vertical  position,  either  upward  or  downward,  water  would  be  trapped 
to  a  considerable  extent. 


Q.  12.  What  is  a  water  hammer?  Name  some  of  the  conditions  under 
which  they  occur. 

Ans.  12.  A  water  hammer  is  the  snapping  and  pounding  so  frequently 
heard  in  pipe  systems.  In  its  mild  form  it  is  simply  annoying,  but  often 
it  occurs  in  a  violent  form  and  becomes  highly  dangerous.  A  water  ham- 
mer is  produced  under  the  following  conditions:  A  pipe  laying  horizontal, 
imperfectly  drained  and  containing  more  or  less  water,  has  live  steam  turned 
into  it ;  this  live  steam  striking  the  water  will  almost  instantly  condense  and 
create  a  small  area  of  vacuum  into  which  the  water  rushes  with  great  force, 
and  then  coming  to  rest,  resulting  in  a  distinct  shock.  The  strength  of  the 
snapping  or  pounding  depends  upon  the  length  of  time  it  takes  to  condense 
the  steam  admitted  to  the  pipe. 


Q.  13.     What  is   the  best   method  of  preventing  wasting  or  pitting  in 
underground  steam  lines,  used  for  returning  condensation? 

Ans.  13.     They  should  be  of  cast  iron  or  brass  and  should  be  run  in  dry 
boxes  or  trenches  out  of  contact  with  the  earth. 


Q.  14.  Describe  the  differences  between  the  "compression"  system  of 
refrigeration,  and  the  one  commonly  termed  the  ' '  absorption ' '  system. 

Ans.  14.  A  compression  system  of  refrigeration  is  operated  by  means 
of  a  gas  pump  or  compressor.  The  operations  are  compression  of  the  gas 
by  the  compressor  to  about  150  Ibs.  Next  a  withdrawal  of  the  heat  caused 
by  compression  by  means  of  cold  water  in  contact  with  the  pipes  containing 
the  ammonia  gas.  Next  the  expansion  of  the  liquid  and  absorption  by  it  of 
the  heat  of  brine  water  or  air  to  be  cooled  in  their  return  to  the  compressor  to 
complete  another  cycle;  It  is  an  alternate  compression  and  expansion  of  the 
refrigerant. 

In  the  absorption  method  in  a  still,  aqua  ammonia  is  used  con- 
taining 26%  solution  of  ammonia  in  water  which  is  put  into  a  vessel 
and  a  coil  of  steam  pipe  is  run  through  the  vessel.  The  heat  of  the  steam 
heats  the  ammonia  and  water,  causing  the  ammonia  to  expand  and  evaporate 
to  a  pressure  of  about  150  Ibs.  The  gas  and  some  condensed  water  pass  out 
of  the  still  to  the  dehydrating  coil.  The  coil  is  enclosed  in  a  tank  which  is 
filled  with  water  at  a  temperature  of  about  150  degrees  where  the  water-vapor 
condenses  and  the  ammonia  remains  a  gas.  The  gas  and  water  flow  to  a 
water  separator  w-here  the  water  goes  back  to  the  still  and  the  gas  completes 
the  cycle  as  in  a  compression  system. 

40 


Q.  15.'     How   can   transparent    ice   be   made,   by   artificial   means,    from 
clear  water  that  has  not  been  distilled  or  boiled? 

Ans.  15.     By  gentle  agitation  of  the  water  to  be  frozen. 


Q.  16.     Why  should  an  indicator  card  be  as  long  as  possible? 

Ans.  16.  So  as  to  magnify  the  different  lines  such  as  admission  and 
expansion  and  to  separate  the  important  points  as  cut  off  release  and  ex- 
haust closure,  making  them  all  as  distinct  and  prominent  as  possible.  A  long 
card  more  readily  adapts  itself  to  graphical  measurements  and  proofs. 


Q.  17.     Define  the  term  "superheated  steam." 

Ans.  17.  The  term,  superheated  steam,  means  steam  which  has  a  higher 
temperature  than  that  normal  to  its  pressure,  or  that  contains  more  heat 
than  it  is  possible  to  contain  while  in  contact  with  water.  Steam  cannot  be 
superheated  when  it  is  in  direct  contact  with  water. 


Q.  18.  (a).  What  are  the  advantages  and  disadvantages  of  using  super- 
heated steam  ? 

(b).  What  engine  valve  gears  are  best  adapted  for  using  superheated 
steam? 

Ans.  18.  (a).  The  advantage  of  superheated  steam  is  that,  containing 
a  greater  amount  of  heat  than  that  normal  to  its  pressure,  it  reduces  the 
amount  of  condensation  in  the  cylinders  to  a  minimum. 

The  disadvantage  is  the  difficulty  of  lubricating  the  surfaces  of  valves 
and  cylinders,  as  the  high  temperature  tends  to  burn  the  lubricating  mate- 
rial. The  complex  apparatus  for  superheating  steam  is  somewhat  of  a  dis- 
advantage also. 

(b).    Poppet  valves  are  best  adapted  for  using  superheated  steam. 


Q.  19.  If  steam  enters  an  engine  cylinder  at  335°  F.  and  leaves  it  at 
225°  F.,  what  becomes  of  the  temperature  represented  by  the  drop  of  110°; 
no  account  need  be  taken  of  losses  by  radiation. 

Ans.  19.  The  110°  F.  did  not  disappear  but  simply  became  latent,  i.  e., 
they  are  required  to  keep  the  steam  in  a  more  expanded  form  or  rather  at  a 
greater  volume.  If  the  steam  was  not  released  at  225°  F.  and  no  heat  lost 
by  radiation  the  original  temperature  (335°  F.)  would  be  obtained  again  if 
the  piston  would  compress  the  steam  back  again  to  the  original  volume. 


Q.  20.     Describe  a  gravity  heating  system. 

Ans.  20.  A  gravity  heating  system  is  a  system  where  the  steam,  after 
condensation  in  the  radiating  surfaces,  will,  in  the  form  of  condensation  be 
returned  by  gravity  to  the  boiler,  the  boiler  being  the  lowest  part  of  the 
system.  The  returns  may  also  return  to  any  suitable  receptacle  and  enter 
the  boiler  by  means  of  a  pump,  in  which  case,  the  boiler  may  be  located  at 
any  point. 


Q.  21.     Describe  a  vacuum  heating  system. 

Ans.  21.  A  vacuum  heating  system  has  its  returns  exhausted  by  means 
of  a  pump  or  ejector,  creating  a  vacuum  in  the  system.  When  exhaust  steam 
of  low  pressure  is  used  this  is  very  efficient,  as  the  steam  circulates  thor- 
oughly and  rapidly.  Steam  at  a  pressure  below  the  atmosphere  can  be  used 
if  the  pump  or  ejector  handling  the  returns  maintains  a  vacuum  of  suf- 
ficient degree.  In  some  cases  a  vacuum  of  8  to  10  inches  is  maintained  in 
the  exhaust  pipe  of  the  engine.  In  order  to  secure  this  result  the  system  must 
be  free  from  all  leaks,  and  a  sufficient  radiating  surface  must  be  available 
to  condense  the  exhaust  steam. 


Q.  22.  Give  several  simple  and  easily  applied  tests  whereby  the  hardness 
of  boiler  feed  water,  or  the  presence  of  acid  in  same,  may  be  detected. 

Ans.  22.  A  few  drops  of  a  solution  of  good  soap  in  alcohol  if  put  in  a 
vessel  of  water  will  turn  it  quite  milky  if  the  water  is  hard,  and  if  soft  will 
remain  clear.  The  harder  the  water  the  less  effect  the  soap  has  on  it  be- 
cause the  mineral  matter  neutralizes  so  much  of  it.  Water  which  will  turn 
blue  litmus  paper  red  before  boiling  the  water  but  not  after  boiling  contains 
carbonic  acid. 


Q.  23.  In  making  a  calorimeter  test,  what  is  the  best  method  of  se- 
curing a  fair  sample  of  the  steam  passing  through  the  pipe  from  which  sam- 
ple is  to  be  taken  ? 

Ans.  23.  A  barrel  calorimeter  test  is  one  of  the  best  methods.  It  con- 
sists of  a  barrel  that  will  hold  400  or  500  pounds  of  water  placed  on  plat- 
form scales.  A  pipe  or  hose  leading  into  it  from  the  source  of  steam  supply, 
as  near  the  throttle  as  possible.  A  valve  to  admit  steam  when  needed.  The 
pipe  or  hose  should  be  perforated  and  closed  at  end.  A  thermometer  is  also 
used  to  show  the  difference  in  the  temperature  of  the  water  before  and  after 
the  steam  is  admitted  to  the  water. 


Q.  24.     What  is  a  draft  gauge,  how  is  it  constructed,  and  how  is  it  used? 

Ans.  24.  A  draft  gauge  is  an  instrument  used  to  ascertain  the  amount 
of  draft  in  a  chimney  or  uptake  of  a  boiler.  This  instrument  is  made  in 
various  forms,  but  all  work  on  the  same  principle.  In  its  simplest  form  it 
consists  of  a  U-shaped  graduated  glass  tube  partially  filled  with  water,  one 
end  of  which  is  connected  by  means  of  a.  suitable  piece  of  flexible  tubing  or 
pipe,  to  the  chimney  or  uptake  the  draft  of  which  is  to  be  ascertained;  the 
other  end  of  the  glass  tube  should  be  open  to  the  atmosphere.  The  differ- 
ence in  the  height  of  the  water  in  the  two  legs  of  the  tube  is  the  measure- 
ment of  the  draft,  and  is  stated  in  inches. 


Q.  25.  Describe  the  construction  and  operation  of  a  steam  pressure 
gauge.  Why  is  a  loop  used  in  connecting  the  gauge  to  the  boiler? 

Ans.  25.  Steam  gauges  are  constructed  with  a  tube  nearly  elliptical  in 
cross  section.  This  tube  is  bent  nearly  into  a  circle;  as  pressure  is  admitted 
inside  the  tube  it  has  a  tendency  to  straighten  out,  which  is  resisted  by  its 
own  stiffness.  The  motion  of  the  end  of  the  tube  is  communicated  to  a 
pointer  by  a  rack  and  pinion.  A  loop  or  syphon  is  placed  in  the  connection 
between  the  boiler  and  steam  gauge  to  trap  water  in  the  pipe  so  that  the 
steam  cannot  enter  the  tube  and  thereby  affect  its  stiffness. 

42 


Q.  26.  Is  there  any  difference  in  the  construction  and  principle  of  opera- 
tion between  pressure  and  vacuum  gauges? 

Ans.  26.  There  is  no  difference  in  the  construction  and  principle  of 
pressure  gauges  and  vacuum  gauges.  Any  pressure  gauge  will  indicate  a 
vacuum  by  allowing  the  pointer  to  travel  below  the  zero  mark.  However, 
in  order  to  correctly  read  the  degree  of  vacuum,  the  gauge  dial  would  have 
to  be  properly  graduated.  In  a  vacuum  gauge  the  pointer  is,  by  suitable 
connection  to  the  elliptical  tube,  made  to  travel  from  left  to  right,  the  same 
as  the  pointer  in  a  steam  gauge,  and  reads  from  0  to  30,  representing  inches 
of  vacuum.  The  reading  from  left  to  right  is  simply  a  matter  of  con- 
venience. 


Q.  27.     What  is  a  compound  gauge,  and  where  is  it  ordinarily  used? 

Ans.  27.  The  compound  gauge  has  its  dial  graduated  in  such  a  manner 
that  both  pressure  above  the  atmosphere,  as  well  as  pressure  below  the  at- 
mosphere, can  be  read  from  it.  Its  dial  has  the  zero  mark  somewhere  near 
the  top,  reading  to  the  left,  from  0  to  30,  representing  inches  of  vacuum,  and 
to  the  right,  reading  pounds  of  pressure  above  atmosphere.  Sometimes,  in 
compound  gauges,  the  vacuum  is  also  indicated  in  pounds,  reading,  of  course, 
from  0  to  15.  Compound  gauges  are  necessary  where  the  pressure  ranges 
below,  as  well  as  above,  the  atmosphere  pressure.  The  receivers  of  com- 
pound engines  are  usually  fitted  with  compound  gauges. 


Electricity. 


Q.  1.  Define,  in  a  general  way,  the  difference  between  direct  current 
and  alternating  current. 

Ans.  1.     Direct  current  is  that  which  flows  continuously  in  one  direction. 

Alternating  current  is  that  which  changes  its  direction  of  flow;  this 
change  of  direction  may  vary  from  twenty-five  to  ten  thousand  times  a 
second. 


Q.  2.  What  is  a  solenoid,  and  for  what  purposes  is  such  a  device  best 
adapted? 

Ans.  2.  A  solenoid  is  an  electric  magnet  made  out  of  a  hollow  core 
wound  with  insulated  wire,  and  although  not  as  strong  as  a  magnet  with  a 
solid  core  would  be,  owing  to  the  fact  that  the  armature  of  the  magnet 
can  have  a  long  range  of  action  and  without  excessive  variation  in  the  pull 
exerted  upon  it  by  the  coil,  a  solenoid  is  preferable  where  long  range  of 
armature  action  is  desired.  Arc  lamps  and  various  electrical  instruments 
are  equipped  with  a  solenoid. 


Q.  3.  What  is  meant  by  the  term  "booster  set,"  and  under  what  con- 
ditions is  it  advantageous  to  use  such  apparatus  in  electric  lighting  or 
power  work? 

Ans.  3.  A  "  booster ' '  set  consists,  usually,  of  a  motor  and  generator 
mounted  upon  the  same  shaft,  the  motor  using  station  voltage,  and  the  gen- 
erator also  receiving  station  voltage  at  its  negative  terminals  and  raising, 
or  boosting,  it  up  to  a  higher  voltage. 

In  electric  lighting  and  electric  power  work,  this  method  is  often  used 
lo  send  current  to  outlying  districts  where  the  long  distance  transmission 
would  cause  a  sufficient  drop  in  voltage,  from  that  at  station,  to  give  poor 
service. 


Q.  4.     What  is  an  electric  step-up  transformer? 

Ans.  4.  Step-up  transformers  consist  of  an  iron  core  made  of  thin 
sheets,  on  which  are  wound  two  sets  of  coils,  called  the  primary  and  sec- 
ondary windings;  the  primary  windings,  supplied  by  the  lower  potential, 
creates  lines  of  force  in  the  core  which  may  be  considered  to  continuously 
expand  and  contract,  rapidly. 

These  lines  of  force  are  "cut"  by  the  secondary  windings  and,  conse- 
quently, an  electromotive  is  induced  in  the  secondary  winding,  which  fur- 
nishes current  to  the  high  pressure  mains. 

It  may  be  said  that  step-down  transformers  are  constructed  on  similar 
lines,  the  only  difference  being  in  the  method  of  winding  the  primary  and 
secondary  coils. 

44 


Q.  5.  Why  is  direct  current  required  to  excite  the  fields  of  an  alter- 
nating current  generator? 

Ans.  5.  It  requires  current  flowing  continuously  in  the  same  direction 
to  excite  the  fields  of  any  magnet;  if  alternating  current  were  used,  the  field 
would  lose  its  magnetism  at  each  alternation  of  the  current,  at  the  zero 
point.  Alternating  current  dynamos  derive  the  direct  current  necessary  for 
their  fields  from  a  direct  current  dynamo,  known  as  the  exciter. 


Q.  6.  Describe  the  material  used  in  the  construction  of  an  electro-mag- 
net, also  the  method  of  constructing  the  magnet,  and  state  what  limits  the 
magnetic  force  of  an  electro-magnet. 

Ans.  6.  Iron  is  used  for  commercial  electro-magnets,  as  it  remains  a 
magnet  only  so  long  as  current  flows  around  it,  whereas  steel  would  for  a 
long  while  retain  the  magnetic  qualities  after  once  being  induced.  The 
magnetic  force  is  limited  by  the  quantity  of  current  flowing  around  the  mag- 
netic core  and  the  amount  of  iron  and  its  permeability  contained  in  the  core 
of  the  magnet. 


Q.  7.     What  voltage  is  most  economical  for  use  on  a  combination  light- 
ing and  motor  load,  and  why? 

Ans.  7.     The  most  economical  would  be  220  volt  direct  current  (3)  three 
wire  system  on  account  of  cheapness  to  install. 


Q.  8.     Explain  the  meaning  of  volt,  ampere  and  ohm. 

Ans.  8.  (a).  The  volt  is  the  unit  of  electromotive  force,  and  can  best 
be  compared  with  the  pound  as  used  in  connection  with  steam,  water  or  air 
pressures ;  it  represents  the  difference  in  potential  which  tends  to  force  a 
flow  of  current  through  a  conductor. 

(b).  The  ampere  is  a  term  used  for  the  quantity  of  current  flowing  in 
a  circuit,  and  is  the  accepted  unit  of  quantity. 

(c).  The  ohm  is  the  unit  whereby  the  resistance  in  an  electric  circuit  is 
measured. 

The  three  foregoing  terms  bear  a  close  relationship  one  with  the  other. 


Q.  9.     In  what  way  do  ohms  affect  amperes? 

Ans.  9.  The  increase  or  diminishing  of  the  number  of  ohms  will  di- 
rectly affect  the  number  of  amperes;  in  other  words,  the  current  varies  in- 
versely with  the  resistance. 


Q.  10  WThat  is  meant  by  the  terms  of  (a)  natural  magnet  and  (b)  an 
electro  or  induced  magnet? 

Ans.  10.  (a).  A  natural  magnet  is  a  magnet  that  exists  in  a  natural 
state,  such  as  magnetic  ore,  generally  called  the  lodestone. 

(b).  An  electro  or  induced  magnet  is  a  magnet  only  while  an  electric 
current  is  passed  around  it  by  means  of  windings  of  electric  wire,  or  if  a 
substance  lays  in  a  field  of  magnetic  force  and  thereby  becomes  magnetized. 

45 


Q.  11.  What  class  of  apparatus  is  generally  found  in  sub-stations  for 
the  transmission  of  electricity,  and  what  are  the  separate  functions  of  each 
piece  of  apparatus? 

Ans.  11.  Sub-stations  apparatus  differs  according  to  conditions,  but  one 
or  more  of  the  following  will  be  found: 

Step-down  transformers,  to  reduce  voltage. 

Eotary  converters  to  change  the  current  from  A.  C.  to  D.  C.  current. 

Frequency  changer  to  change  to  lower  frequency  where  motor  load  only 
is  used. 

Boosters  to  raise  voltage  on  line. 

Storage  batteries  to  relieve  generator  during  heavy  loads,  also  to  steady 
the  load  where  variation  is  great. 

Lightning  arresters.  And  switch-board  with  controlling  apparatus  for 
whatever  kind  installed. 


Q.  12.  Explain  what  is  meant  by  electric  lamps  placed  in  series,  and 
how  it  affects  the  voltage  and  candle-power. 

Ans.  12.  Lamps  placed  in  series  means  that  they  are  placed  one  after 
another  on  the  same  circuit,  the  current  in  the  circuit  passing  through  each 
lamp.  For  illustration,  five  110  volt  16  candle  power  lamps,  each  using  one- 
half  ampere,  are  to  be  put  on  a  circuit  where  the  voltage  is  550;  each  lamp 
is  then  in  series  and  uses  current  at  a  potential  of  110  volts,  thus  dividing 
the  potential  of  550  equally  among  the  five  lamps.  The  power  used  in  such 
a  case  would  be  5 X. 5X110=275  watts. 


Q.  13.  Given  a  compound  D.  C.  generator,  running  in  multiple,  wired 
up  in  the  usual  way;  if  the  circuit  breaker  opens  and  the  main  switch  is 
pulled,  while  machine  is  still  running,  what  causes  the  pilot  lamp  to  ex- 
plode; and  what  is  the  remedy? 

Ans.  13.  In  the  wiring  up  of  the  generator  only  one  shunt  field  wire 
is  run  from  switchboard  to  generator,  this  wire  is  connected  to  the  machine 
lead  next  to  machine  under  the  fuse.  If  circuit  breaker  is  placed  on  the 
generator  and  it  opens,  the  shunt  field  will  still  be  fed  from  the  bus  bar,  if 
the  main  switch  is  pulled  it  opens  the  shunt  field.  The  pilot  light  is  wired 
from  the  two  machine  leads;  when  main  switch  is  pulled  the  discharge  or 
kick  from  the  fields  explodes  the  lamp.  To  remedy  the  trouble  either  change 
the  circuit  breaker  to  where  it  will  not  cut  the  field  away  from  the  arma- 
ture when  it  opens  or  cut  the  field  wire  off  of  the  machine  lead  and  run  two 
wires  to  the  generator;  tap  one  at  the  top  of  circuit  breaker,  or  next  to  the 
generator,  connect  this  wire  to  rheostat,  tap  the  other  wire  to  the  shunt 
field  so  as  to  allow  the  armature  to  absorb  the  kick;  the  opening  of  the 
breaker  will  have  no  effect  on  the  pilot-light. 


Q.  14.  What  is  meant  by  the  term  "compound  wound  electric  genera- 
tort"  What  feature  of  construction  would  determine  in  your  opinion  that 
a  generator  was  compound  wound? 

Ans.  14.  It  is  meant  that  this  generator  has  its  field  magnets  wound 
with  two  sets  of  coils,  one  of  which  is  connected  in  series,  and  the  other  one 
in  parallel,  with  the  armature  and  the  external  circuit. 

By  noting  how  the  wiring  from  the  field  magnets  and  the  armature  wires 
or  cables  are  connected  up. 

46 


Q.  15.     What  is  meant  by  the  term  "constant  current  generators!" 

Ans.  15.     A  constant  current  generator  is  one  which  does  not  vary;  al- 
though the  voltage  may  vary  the  amount  of  current  is  constant. 


Q.'  16.  Explain  the  term  of  neutral  point  in  connection  with  electric 
generators. 

Ans.  16.  The  neutral  points  of  a  generator  are  the  positions  on  the 
commutator  between  which  the  difference  in  potential  is  greatest,  and  where 
there  is  the  least  difference  in  potential  between  adjacent  bars.  These  points 
are  diametrically  opposite. 


Q.  17.     Explain  the  term  lead  in  connection  with  electric  generators. 

Ans.  17.  Lead  is  the  term  applied  to  the  slight  forward  movement, 
which  it  is  necessary  to  give  the  brushes  in  order  to  avoid  sparking  with  the 
increase  of  load,  due  to  the  fact  of  a  magnetic  reaction  of  the  armature  due 
to  the  heavier  load.  Increase  the  lead  in  the  direction  of  rotation ;  decrease 
in  the  opposite  direction. 


Q.  18.     What  are  the  conditions  when  an  electric  generator  is  given: 
(a)   More  lead!     (b)  Less  lead? 


Ans.  18.     (a).     An  increase  of  load, 
(b).     A  decrease  of  load. 


Q.  19.  With  a  generating  unit  consisting  of  a  cross-compound  engine 
of  the  Corliss  type,  and  an  alternator,  describe  method  of  starting  same, 
bringing  it  up  to  speed  and  cutting  it  in  on  the  load.  This  unit  is  supposed 
to  operate  in  conjunction  with  others. 

Ans.  19.  Start  up  the  condenser  and  turn  on  steam  to  the  high  pressure 
cylinder  and  use  the  bypass  to  the  low  pressure  cylinder.  Let  the  engine 
warm  up  for  ten  minutes  or  so,  and  while  engine  is  warming,  oil  up.  Then- 
start  engine,  running  slowly  for  about  15  minutes,  then  bring  engine  up  to 
speed,  throw  in  field  switch,  build  up  voltage  and  when  in  step  with  other 
generator  throw  in  main  switch. 


Q.  20.     Can  a  D.  C.  compound  wound  motor  of   large   size   be    started 
under   full  load,  without  a  starting  box? 

Ans.  20.     Yes;  by  disconnecting  the  shunt  and  starting  as  a  series  mo- 
tor after  it  is  up  to  speed  or  nearly  so  put  in  the  shunt  field. 


Q.  21.  Explain  the  method  of  winding  electric  motors  of  the  following 
types: 

(a).  Shunt  wound, 
(b).  Series  wound, 
(c).  Compound  wound. 

Ans.  21.  (a).  In  a  shunt-wound  motor  the  current  for  exciting  the 
fields  is  taken  from  the  main  circuit,  but  only  in  sufficient  amount  for  ex- 
citation purposes,  and  forms  a  by-path  in  parallel  with  the  main  circuit. 

47 


(b)  In   a   series-wound   motor  the   whole  of   the   main    circuit   passes 
through  the  wires  conveying  the  current  to  excite  the  fields. 

(c)  In  a  compound-wound  motor  there  are  two  circuits,  one  containing 
many  turns  of  small  wire,  through  which  part  of  the  main  current  passes, 
and  another  consisting  of  a  lesser  number  of  turns  of  large  wire,  through 
which  the  whole  of  the  main  circuit  passes,  with  the  exception  of  the  amount 
passing  through  the  circuit  formed  by  the  smaller  wires.     This  type  is  a 
combination  of  the  shunt  and  series  types,  as  described  in  (a)  and  (b). 


Q.  22.     What  effect  does  the  strength  of  the  fields  have  upon  the  speed 
of  a  direct  current  motor? 

Ans.  22.     Decreasing  the  strength  of  the  fields  increases  the  speed  of 
the  motor,  and  increasing  the  strength  of  the  fields  decreases  the  speed. 


Q.  23.  What  is  the  difference  between  a  synchronous  motor,  and  an  in- 
duction motor? 

Ans.  23.  A  synchronous  motor  has  its  field  excited  from  some  direct 
current  source,  while  its  armature  takes  current  oflf  the  alternating  current 
line;  whereas  the  fields  of  an  induction  motor  are  supplied  with  alternating 
current,  and  the  armature  is  not  connected  to  any  source  of  current,  the  cur- 
rent being  induced  by  the  field. 


The  National  Association  of  Stationary   Engineers. 

ORGANIZED  OCTOBER,  1882.      INCORPORATED  OCTOBER,  1892. 


Four  Hundred  and  Fifty  Subordinate  Associations  with  Twenty  Thousand  Members  in  Forty- 
Eight  States  and  Territories. 


PEEAMBLE. 

This  Association  shall  at  no  time  be  used  for  the  furtherance  of  strikes, 
or  for  the  purpose  of  interfering  in  any  way  between  its  members  and  their 
employers  in  regard  to  wages;  recognizing  the  identity  of  interests  between 
employer  and  employe,  and  not  countenancing  any  project  or  enterprise  that 
will  interfere  with  perfect  harmony  between  them. 

Neither  shall  it  be  used  for  political  or  religious  purposes.  Its  meetings 
shall  be  devoted  to  the  business  of  the  Association,  and  at  all  times  prefer- 
ence shall  be  given  to  the  education  of  engineers,  and  to  securing  of  the 
enactment  of  engineers'  license  laws  in  order  to  prevent  the  destruction  of 
life  and  property  in  the  generation  and  transmission  of  steam  as  a  motive 
power. 


FORMER  PRESIDENTS  AND  YEARS  OF  SERVICE. 

1882-3.  H.   D.   Cozens Providence,  R.   I. 

1883-4.  James  G.  Beckerleg Chicago,  111. 

1884-5.  R.  J.  Kilpatrick St.  Louis,  Mo. 

1885-6.  James  G.  Beckerleg Chicago,  III. 

1886-7.  F.    A.    Foster Bridgeport,    Conn. 

1887.  G.  M.  Barker Boston,  Mass. 

1888.  R.  O.  Smith New  York  City 

1889.  John  Fehrenbatch   Cincinnati,  O. 

1890.  J.  J.  Illingworth   Utica,  N.  T. 

1891.  William   Powell    Cleveland,    O. 

1892.  C.  W.  Naylor Chicago,  111. 

1893.  James   D.   Lynch    Philadelphia,    Pa. 

1894.  M.  D.  Nagle  New  York  City 

1895.  Charles  H.  Garlick Pittsburg,  Pa. 

1896.  J.  W.   Lane Providence,   R.   I. 

1897.  C.   A.   Collett St.   Louis,    Mo. 

1898.  W.  T.  Wheeler New  York  City 

1899.  Herbert  E.  Stone Cambridge,  Mass. 

1900.  P.  E.  Leahy  New  York  City 

1901.  E.   G.  Jacques Detroit,  Mich. 

1902.  R.   G.   Ingleson Cleveland,   O. 

1903.  P.  F.  Hogan,   Boston,  Mass. 

1904.  C.  F.   Wilson    Milwaukee,   Wis. 

1905.  R.  D.  Tomlinson New  York  City 

1906.  T.  N.  Kelsey Lowell,  Mass. 

1907.  J.  F.  Carney New  York  City 

49 


RULES  FOB    CONDUCTING    BOILER    TRIALS,   FORMULATED    BY 

THE   AMERICAN  SOCIETY   OF  MECHANICAL   ENGINEERS. 

KNOWN  AS  THE  CODE  OF  1899. 


I.  DETERMINE  AT  THE  OUTSET  the  specific  object  of  the  proposed  trial, 
whether  it  be  to  ascertain  the  capacity  of  the  boiler,  its  efficiency  a3  a 
steam  generator,  its  efficiency  and  its  defects  under  usual  working  con- 
ditions, the  economy  of  some  particular  kind  of  fuel,  or  the  effect  of 
changes   of  design,  proportion,  or  operation;   and  prepare  for  the  trial 
accordingly. 

II.  EXAMINE   THE   BOILER,   both    outside    and   inside;    ascertain    the 
dimensions-  of   grates,   heating   surfaces,   and    all    important  parts;   and 
make  a  full  record  describing  the  same,  and  illustrating  special  features 
by  sketches.     The  area  of  heating  surface  is  to  be  computed  from  the 
surfaces  of  shells,   tubes,   furnaces,   and  fire-boxes   in   contact  with  the 
fire  or  hot  gases.     The  outside  diameter  of  water-tubes  and  the  inside 
diameter  of  fire-tubes  are  to  be  used  in  the  computation.     All  surfaces 
below  the  mean  water  level  which  have  water  on  on  side  and  products 
of  combustion  on  the  other  are  to  be  considered  as  water  heating  sur- 
face, and  all  surfaces  above  the  mean  water  level  which  have  steam  on 
one  side  and  products  of  combustion  on  the  other  are  to  be  considered 
as  superheating  surface. 

III.  NOTICE  THE  GENERAL  CONDITION  of  the  boiler  and  its  equipment, 
and  record  such  facts  in  relation  thereto  as  bear  upon  the  objects  in 
view. 

If  the  object  of  the  trial  is  to  ascertain  the  maximum  economy  or 
capacity  of  the  boiler  as  a  steam  generator,  the  boiler  and  all  its  appur- 
tenances should  be  put  in  first  class  condition.  Clean  the  heating  sur- 
face inside  and  outside,  remove  clinkers  from  the  grates  and  from  the 
sides  of  the  furnace.  Remove  all  dust,  soot,  and  ashes  from  the  cham- 
bers, smoke  connections  and  flues.  Close  air  leaks  in  the  masonry  and 
poorly  fitted  cleaning  doors.  See  that  the  damper  will  open  wide  and 
close  tight.  Test  for  air  leaks  by  firing  a  few  shovels  of  smoky  fuel 
and  immediately  closing  the  damper,  observing  the  escape  of  smoke 
through  the  crevices,  or  by  passing  the  flame  of  a  candle  over  cracks 
in  the  brickwork. 

IV.  DETERMINE  THE  CHARACTER  OF  THE  COAL  to  be  used.     For  tests 
of  the  efficiency  or  capacity  of  the  boiler  for  comparison  with  other  boil- 
ers, the  coal  should,  if  possible,  be  of  some  kind  which  is  commercially 
regarded   as  a   standard.     For   New  England   and   that   portion  of   the 
country   east   of    the    Allegheny   Mountains,    good    anthracite   egg   coal, 
containing  not  over  ten  per  cent,  of  the  ash,  and  the  semi-bituminous  Clear- 
field,  (Pa.),  Cumberland  (Md.),  and  Pocahontas  (Va.),  are  thus  regarded. 
West  of  the  Allegheny  Mountains,  Pocahontas,   (Va.),  and  New  River, 
(W.  Va.),  semi-bituminous,   and  Youghiogheny  or  Pittsburg  bituminous 
coals   are   recognized   as   standards.     There  is  no  special  grade  of  coal 
mined  in  the  Western  States  which  is  widely  recognized  as  of  superior 
quality  or  considered  as  a  standard  coal  for  boiler  testing.    Big  Muddy 
lump,  an  Illinois  coal  mined  in  Jackson  County,  111.,  is  suggested  as  being 
of  sufficiently  high  grade  to  answer  these  requirements  in  districts  where 

50 


it  is  more  conveniently  obtainable  than  the  other  coals  mentioned  above. 
For  tests  made  to  determine  the  performance  of  a  boiler  with  a  par- 
ticular kind  of  coal,  such  as  may  be  specified  in  a  contract  for  the  sale 
of  a  boiler,  the  coal  used  should  not  be  higher  in  ash  and  in  moisture 
than  that  specified,  since  increase  in  ash  and  moisture  above  a  stated 
amount  is  apt  to  cause  a  falling  off  of  both  capacity  and  economy  in 
greater  proportion  than  the  proportion  of  such  increase. 

V.  ESTABLISH  THE  CORRECTNESS  OF  ALL  APPARATUS  used  in  the  test 
for  weighing  and  measuring.  These  are: 

1.  Scales  for  weighing  coal,  ashes,  and  water. 

2.  Tanks,  or  water-meters,  for   measuring  water.     Water-meters,   as 
a    rule    should   be   used   only   as   a    check   on   other  measurements.      For 
accurate  work,  the  water  should  be  weighed  or  measured  in  a  tank. 

3.  Thermometers    and   pyrometers    for   taking    temperatures   of    air, 
steam,  feed-water,  waste  gases,  etc. 

4.  Pressure  gauges,  draught  gauges,  etc. 

The  kind  and  location  of  the  various  pieces  of  testing  apparatus 
must  be  left  to  the  judgment  of  the  person  conducting  the  test;  always 
keeping  in  mind  the  main  object,  that  is,  to  obtain  authentic  data. 

VT.      SEE  THAT  THE  BOILER  IS  THOROUGHLY  HEATED  to  its  USUal  working 

temperature  before  the  trial.  If  the  boiler  is  new  and  of  a  form  provided 
with  a  brick  setting,  it  should  be  in  regular  use  at  least  a  week  before 
the  trial,  so  as  to  dry  and  heat  the  walls.  If  it  has  been  laid  off  and 
become  cold,  it  should  be  worked  before  the  trial  until  the  walls  are 
well  heated. 

VII.  THE  BOILER  AND  CONNECTIONS  should  be  proved  to  be  free  from 
leaks  before  beginning  a  test,  and  all  water  connections,  including  below 
and  extra  feed  pipes,  should  be  disconnected,  stopped  with  blank  flanges, 
or  bled  through  special  openings  beyond  the  valves,  except  the  particular 
pipe  through  which  water  is  fed  to  the  boiler  during  the  trial.  During 
the  test  the  blow-off  and  feed  pipes  should  remain  exposed  to  view. 

If  an  injector  is  used,  it  should  receive  steam  directly  through  a  felted 
pipe  from  the  boiler  being  tested.* 

If  the  water  is  metered  after  it  passes  the  injector,  its  temperature 
should  be  taken  at  the  point  where  it  leaves  the  injector.  If  the  quantity 
is  determined  before  it  goes  to  the  injector  the  temperature  should  be 
determined  on  the  suction  side  of  the  injector,  and  if  no  change  of  tem- 
perature occurs  other  than  that  due  to  the  injector,  the  temperature  thus 
determined  is  properly  that  of  the  feed  water.  When  the  temperature 
changes  between  the  injector  and  the  boiler,  as  by  the  use  of  a  heater 
or  by  radiation,  the  temperature  at  which  the  water  enters  and  leaves 
the  injector  and  that  at  which  it  enters  the  boiler  should  all  be  taken. 
In  that  case  the  weight  to  be  used  is  that  of  the  water  leaving  the 
injector,  computed  from  the  heat  units  if  not  directly  measured,  and  the 
temperature,  that  of  the  water  entering  the  boiler. 

Let  w=weight  of  water  entering  the  injector. 
a;=weight  of  steam  entering  the  injector. 

^j=heat  units  per  pound  of  water  entering  the  injector. 

7ij=heat  units  per  pound  of  steam  entering  the  injector. 

A3=heat  units  per  pound  of  water  leaving  injector. 
Then  w+x — weight  of  water  leaving  injector. 


*  In  feeding  a  boiler  undergoing  test  with  an  injector  taking  steam  from  another 
boiler,  or  from  the  main  steam  pipe  from  several  boilers,  the  evaporative  results  may 
be  modified  by  a  difference  in  the  quality  of  the  steam  from  such  source  compared  with 
that  supplied  by  the  boiler  being  tested,  and  in  some  cases  the  connection  to  the 
injector  may  act  as  a  drip  for  the  main  steam  pipe.  If  it  is  known  that  the  steam 
from  the  main  pipe  is  of  the  same  pressure  and  quality  as  that  furnished  by  the  boiler 
undergoing  the  test,  the  steam  may  be  taken  from  such  main  pipe. 

51 


A.-A. 

See  that  the  steam  main  is  so  arranged  that  water  of  condensation 
cannot  run  back  into  the  boiler. 

VIII.  DURATION  OF  THE  TEST — For  tests  made  to  ascertain  either  the 
maximum  economy  or  the  maximum  capacity  of  a  boiler,  irrespective  of 
the  particular  class  of  service  for  which  it  is  regularly  used,  the  duration 
should  be  at  least  ten  hours  of  continuous  running.     If  the  rate  of  com- 
bustion exceeds  25  pounds  of  coal  per  square  foot  of  grate  surface  per 
hour,  it  may  be   stopped   when  a   total  of  250  pounds  of  coal  has  been 
burned   per  square  foot  of  grate. 

In  cases  where  the  service  requires  continuous  running  for  the  whole 
24  hours  of  the  day,  with  shifts  of  firemen  a  number  of  times  during  that 
period,  it  is  well  to  continue  the  test  for  at  least  24  hours. 

When  it  is  desired  to  ascertain  the  performance  under  the  working 
conditions  of  practical  running,  whether  the  boiler  be  regularly  in  use 
24  hours  a  day  or  only  a  certain  number  of  hours  out  of  each  24,  the  fires 
being  banked  the  balance  of  the  time,  the  duration  should  not  be  less 
than  24  hours. 

IX.  STARTING  AND  STOPPING  A  TEST — The  conditions  of  the  boiler  and 
furnace  in  all  respects  should  be,  as  nearly  as  possible,  the  same  at  the 
end  as  at  the  beginning  of  the  test.     The  steam  pressure  should  be  the 
same;   the  water  level  the  same;  the  fire  upon  the  grates  should  be  the 
same  in  quantity  and  condition;  and  the  walls,  flues,  etc.,  should  be  of 
the  same  temperature.    Two  methods  of  obtaining  the  desired  equality  of 
conditions  of  the  fire  may  be  used,  viz.;  those  which  were  called  in  the 
Code  of  1885  "the  standard  method"  and  "the  alternate  method,"  the 
latter  being  employed  where  it  is  inconvenient  to  make  use  of  the  standard 
method,  t 

X.  STANDARD  METHOD  OF  STARTING  AND  STOPPING  A  TEST — Steam  being 
raised  to  the  working  pressure,  remove  rapidly  all  the  fire  from  the  grate, 
close  the  damper,  clean  the  ash-pit,  and  as   quickly  as  possible  start  a 
new  fire  with   weighed  wood   and   coal,  noting  the  time   and   the  water 
level*  while  the  water  is  in  a  quiescent  state,  just  before  lighting  the  fire. 

At  the  end  of  the  test  remove  the  whole  fire,  which  has  been  burned 
low,  clean  the  grates  and  ash-pit,  and  note  the  water  level  when  the  water 
is  in  a  quiescent  state,  and  record  the  time  of  hauling  the  fire.  The  water 
level  should  be  as  nearly  as  possible  the  same  as  at  the  beginning  of  the 
test.  If  it  is  not  the  same,  a  correction  should  be  made  by  computation, 
and  not  by  operating  the  pump  after  the  test  is  completed. 

XI.  ALTERNATE  METHOD  OF  STARTING  AND  STOPPING  A  TEST. — The  boiler 
being  thoroughly  heated  by  a  preliminary  run,  the  fires  are  to  be  burned 
low  and  well  cleaned.    Note  the  amount  of  coal  left  on  the  grate  as  nearly 
as  it  can  be  estimated;  note  the  pressure  of  steam  and  the  water  level. 
Note  the  time  and  record  it  as  the  starting  time.     Fresh  coal  which  has 
been   weighed   should    now   be    fired.      The    ash-pits    should    be    thoroughly 
cleaned  at  once    after    starting.     Before    the    end    of    the    test    the    fire's 
should  be  burned  low,  just  as  before  the  start,  and  the  fires  cleaned  in 

t  The  Committee  concludes  that  It  is  best  to  retain  the  designations  "standard" 
and  "alternate,"  since  they  have  become  widely  known  and  established  in  the  minds 
of  engineers  and  in  the  reprints  of  the  Code  of  18R5.  Many  engineers  prefer  the 
"alternate"  to  the  "standard"  method  on  account  of  Its  being  less  liable  to  error 
due  to  cooling  of  the  boiler  at  the  beginning  and  end  of  a  test. 

*  The  gauge-glass  should  not  be  blown  out  within  an  hour  before  the  water  levpl 
Is  taken  at  the  beginning  and  end  of  test,  otherwise  an  error  in  the  reading  of  tho 
water  level  may  be  caused  by  a  change  in  the  temperature  and  density  of  the  water  in 
the  pipe  leading  from  the  bottom  of  the  glass  into  the  boiler. 

52 


such  a  manner  as  to  leave  a  bed  of  coal  on  the  grates  of  the  same  depth, 
and  in  the  same  condition,  as  at  the  start.  When  this  stage  is  reached, 
note  the  time  and  record  it  as  the  stopping  time.  The  water  level  and 
steam  pressures  should  previously  be  brought  as  nearly  as  possible  to 
the  same  point  as  at  the  start.  If  the  water  level  is  not  the  same  as  at 
the  start,  a  correction  should  be  made  by  computation,  and  not  by  opera- 
ting the  pump  after  the  test  is  completed. 

XII.  UNIFORMITY    op   CONDITIONS — In    all    trials   made   to   ascertain 
maximum  economy  or  capacity,  the  conditions  should   be  maintained  uni- 
formly constant.     Arrangements  should  be  made   to  dispose  of  the  steam 
so  that  the  rate  of  evaporation  may  be  kept  the  same  from  beginning 
to  end.    This  may  be  accomplished  in  a  single  boiler  by  carrying  the  steam 
through  a  waste-steam  pipe,   the   discharge   from   which   can   be  regulated 
as  desired.     In   a   battery  of  boilers,   in   which   only  one  is  tested,   the 
draft  may  be  regulated  on  the  remaining  boilers,  leaving  the  test  boiler 
to  work  under  a  constant  rate  of  production. 

Uniformity  of  conditions  should  prevail  as  to  the  pressure  of  steam, 
the  height  of  water,  the  rate  of  evaporation,  the  thickness  of  fire,  the 
times  of  firing  and  the  quantity  of  coal  fired  at  one  time,  and  as  to  the 
intervals  between  the  times  of  cleaning  the  fires. 

The  method  of  firing  to  be  carried  on  in  such  tests  should  be  dictated 
by  the  expert  or  person  in  responsible  charge  of  the  test,  and  the  method 
adopted  should  be  adhered  to  by  the  fireman  throughout  the  test. 

XIII.  KEEPING  THE  RECORDS — Take  note  of  every  event  connected  with 
the  progress  of  the  trial,  however  unimportant  it  may  appear.     Kecord  the 
time  of  every  occurrence  and  the  time  of  taking  every  weight  and  every 
observation. 

The  coal  should  be  weighed  and  delivered  to  the  fireman  in  equal 
proportions,  each  sufficient  for  not  more  than  one  hour's  run,  and  a  fresh 
portion  should  not  be  delivered  until  the  previous  one  has  all  been  fired. 
The  time  required  to  consume  each  portion  should  be  noted,  the  time 
being  recorded  at  the  instant  of  firing  the  last  of  each  portion.  It  is 
desirable  that  at  the  same  time  the  amount  of  water  fed  into  the  boiler 
should  be  accurately  noted  and  recorded,  including  the  height  of  the 
water  in  the  boiler  and  the  average  pressure  of  steam  and  temperature 
of  feed  during  the  time.  By  thus  recording  the  amount  of  water  evap- 
orated by  successive  portions  of  coal,  the  test  may  be  divided  into  several 
periods  if  desired,  and  the  degree  of  uniformity  of  combustion,  evapora- 
tion, and  economy  analyzed  for  each  period.  In  addition  to  these  records 
of  the  coal  and  the  feed  water,  half  hourly  observations  should  be  made 
of  the  temperature  of  the  feed  water,  of  the  flue-gases,  of  the  external 
air  in  the  boiler  room,  of  the  temperature  of  the  furnace  when  a  furnace 
pyrometer  is  used,  also  of  the  pressure  of  steam,  and  of  the  readings  of 
the  instruments  for  determining  the  moisture  of  the  steam.  A  log  shouM 
be  kept  on  properly  prepared  blanks  containing  columns  for  record  of 
the  various  observations. 

When  the  "standard  method"  of  starting  and  stopping  the  test  is 
used,  the  hourly  rate  of  combustion  and  evaporation  and  the  horse- 
power should  be  computed  from  the  records  taken  during  the  time  when 
the  fires  are  in  active  condition.  This  time  is  somewhat  less  than  the 
actual  time  which  elapses  between  the  beginning  and  end  of  the  run.  The 
loss  of  time  due  to  kindling  the  fire  at  the  beginning  and  burning  it  out 
at  the  end  makes  this  course  necessary. 

XIV.  QUALITY  OF  STEAM — The  percentage  of  moisture  in  steam  should 
be  determined  by  the  use  of  either  a  throttling  or  a  separating  steam 
calorimeter.     The  sampling  nozzle  should  be  placed  in  the  vertical  steam 
pipe  rising  from  the  boiler.    It  should  be  made  of  lA-inch  pipe,  and  should 
extend   across   the   diameter   of  the   steam   pipe   to  within  half   an  inch 
of  the  opposite  side,  being  closed  at  the  end  and  perforated  with  not  less 

53 


than  twenty  %-inch  holes  equally  distributed  along  and  around  its  cylin- 
drical surface,  but  none  of  these  holes  should  be  nearer  than  i^-inch 
to  the  inner  side  of  the  steam  pipe.  The  calorimeter  and  the  pipe  lead- 
ing to  it  should  be  well  covered  with  felting.  Whenever  the  indications  of 
the  throttling  or  separating  calorimeter  show  that  the  percentage  of 
moisture  is  irregular,  or  occasionally  in  excess  of  three  per  cent.,  the 
results  should  be  checked  by  a  steam  separator  pNced  in  the  steam  pipe 
as  close  to  the  boiler  as  convenient,  with  a  calorimeter  in  the  steam  pipe 
just  beyond  the  outlet  from  the  separator.  The  drip  from  the  separator 
should  be  caught  and  weighed,  and  the  percentage  of  moisture  computed 
therefrom  added  to  that  shown  by  the  calorimeter. 

Superheating  should  be  determined  by  means  of  a  thermometer  placed 
in  a  mercury-well  inserted  in  the  steam  pipe.  The  degree  of  superheating 
should  be  taken  as  the  difference  between  the  reading  of  the  thermometer 
for  superheated  steam  and  the  readings  of  the  same  thermometer  of  sat- 
urated steam  at  the  same  pressure  as  determined  by  a  special  experiment, 
and  not  by  reference  to  steam  tables. 

XV.  SAMPLING  THE  COAL  AND  DETERMINING  ITS  MOISTURE — As  each 
barrow  load  or  fresh  portion  of  coal  is  taken  from  the  coal  pile,  a  repre- 
sentative shovelful  is  selected  from  it  and  placed  in  a  barrel  or  box  in 
a  cool  place  and  kept  until  the  end  of  the  trial.  The  samples  are  then 
mixed  and  broken  into  pieces  not  exceeding  one  inch  in  diameter,  and 
reduced  by  the  processes  of  repeated  quartering  and  crushing  until  a  final 
sample  weighing  about  five  pounds  is  Obtained,  and  the  size  of  the  larger 
pieces  is  such  that  they  will  pass  through  a  sieve  with  %-inch  meshes. 
From  this  sample  two  one-quart,  air-tight  glass  preserving  jars,  or  other 
air-tight  vessels  which  will  prevent  the  escape  of  moisture  from  the 
sample,  are  to  be  promptly  filled,  and  these  samples  are  to  be  kept  for  sub- 
sequent determinations  of  moisture  and  of  heating  value  and  for  chemi- 
cal analyses.  During  the  process  of  quartering,  when  the  sample  has  been 
reduced  to  about  100  pounds,  a  quarter  to  a  half  of  it  may  be  taken 
for  an  approximate  determination  of  moisture.  This  may  be  made  by 
placing  it  in  a  shallow  iron  pan,  not  over  three  inches  deep,  carefully 
weighing  'it  and  setting  the  pan  in  the  hottest  place  that  can  be  found 
on  the  brickwork  of  the  boiler  setting  or  flues  keeping  it  there  for  at  least 
12  hours,  and  then  weighing  it.  The  determination  of  moisture  thus 
made  is  believed  to  be  approximately  accurate  for  anthracite  and  semi- 
bituminous  coals,  and  also  for  Pittsburg  or  Youghiogheny  coal;  but  it  can- 
not be  relied  upon  for  coals  mined  west  of  Pittsburg,  or  for  other  coals 
containing  inherent  moisture.  For  these  latter  coals  it  is  important  that 
a  more  accurate  method  be  adopted.  The  method  recommended  by  the 
Committee  for  all  accurate  tests,  whatever  the  character  of  the  coal, 
is  described  as  follows: 

Take  one  of  the  samples  contained  in  the  glass  jars,  and  subject  it  to 
a  thorough  air  drying,  by  spreading  it  in  a  thin  layer  and  exposing  it  for 
several  hours  to  the  atmosphere  of  a  warm  room,  weighing  it  before  and 
after,  thereby  determining  the  quantity  of  the  surface  moisture  it  con- 
tains. Then  crush  the  whole  of  it  by  running  through  an  ordinary  coffee 
mill  adjusted  so  as  to  produce  somewhat  coarse  grains  (less  than  1-16 
inch),  thoroughly  mix  the  crushed  sample,  select  from  it  a  portion  of  from 
10  to  50  grams,  weigh  it  in  a  balance  which  will  easily  show  a  variation 
as  small  as  1  part  in  1,000,  and  dry  it  in  an  air  or  sand  bath  at  a  temper- 
ature between  240  and  280  degrees  Fahr.  for  one  hour.  Weigh  it  and 
record  the  loss,  then  heat  and  weigh  it  again  repeatedly,  at  intervals  of 
an  hour  or  less,  until  the  minimum  weight  has  been  reached  and  the  weight 
begins  to  increase  by  oxidation  of  a  portion  of  the  coal.  The  difference 
between  the  original  and  the  minimum  weight  is  taken  as  the  moisture 
in  the  air-dried  coal.  This  moisture  test  should  preferably  be  made 
on  duplicate  samples,  and  the  results  should  agree  within  0.3  to  0.4  of 
one  per  cent.,  the  mean  of  the  two  determinations  being  taken  as  the 

54 


correct  result.  The  sum  of  the  percentage  of  moisture  thus  found  and  the 
percentage  of  surface  moisture  previously  determined  is  the  total  moist- 
ure. 

XVI.  TREATMENT  OP  ASHES  AND  REFUSE — The  ashes  and  refuse  are  to 
be  weighed  in  a  dry  state.     If  it  is  found  desirable  to  show  the  principal 
characteristics  of  the  ash,  a  sample  should  be  subjected  to  a  proximate 
analysis   and   the   actual  amount   of   incombustible   material   determined. 
For  elaborate  trials  a  complete  analysis  of  the  ash  and  refuse  should  be 
made. 

XVII.  CALORIC  TESTS  AND  ANALYSIS  OF  COAL. — The  quantity  of  the  fuel 
should  be  determined  either  by  heat  test  or  by  analysis,  or  by  both. 

The  rational  method  of  determining  the  total  heat  of  combustion  is 
to  burn  the  sample  of  coal  in  an  atmosphere  of  oxygen  gas,  the  coal  to  be 
sampled  as  directed  in  Article  XV  of  this  code. 

The  chemical  analysis  of  the  coal  should  be  made  only  by  an  expert 
chemist.  The  total  heat  of  combustion  computed  from  the  results  of  the 
ultimate  analysis  may  be  obtained  by  the  use  of  Dulong's  formula,  pages 
106  and  131. 

It  is  desirable  that  a  proximate  analysis  should  be  made,  thereby 
determining  the  relative  proportions  of  volatile  matter  and  fixed  carbon. 
These  proportions  furnish  an  indication  of  the  leading  characteristics  of 
the  fuel,  and  serve  to  fix  the  class  to  which  it  belongs.  As  an  additional 
indication  of  the  characteristics  of  the  fuel,  the  specific  gravity  should 
be  determined. 

XVIII.  ANALYSIS  OF  FLUE  GASES — The  analysis  of  the  flue  gases  is 
an  especially  valuable  method  of  determining  the  relative  value  of  differ- 
ent methods  of  firing,  or  of  different  kinds  of  furnaces.     In  making  these 
analyses  great  care  should  be  taken  to  procure  average  samples — since 
the  composition  is  apt  to  vary  at  different  points  of  the  flue.     The  com- 
position is  also  apt  to  vary  from  minute  to  minute,  and  for  this  reason  the 
drawings  of  gas  should  last  a  considerable  period  of  time.     Where  com- 
plete determinations  are  desired,  the  analyses  should  be  intrusted  to  an 
expert  chemist.     For  approximate  determinations  the  Orsat  or  the  Hem- 
pel  apparatus  may  be  used  by  the  engineer. 

For  a  continuous  indication  of  the  amount  of  carbonic  acid  (CO2)  pres- 
ent in  the  flue-gases,  an  instrument  may  be  employed  which  shows  the 
weight  of  the  sample  of  gas  passing  through  it. 

XIX.  SMOKE  OBSERVATIONS — It   is  desirable  to  have  a  uniform  sys- 
tem of  determining  and  recording  the  quantity  of  smoke  produced  where 
bituminous   coal   is   used.      The    system   commonly   employed   is   to   express 
the    degree   of    smokiness   by   means    of   percentages    dependent    upon    the 
judgment  of  the    observer.     The    Committee    does    not    place    much    value 
upon  a  percentage  method,  because  it  depends  so  largely  upon  the  personal 
element,  but  if  this  method  is  used,  it  is  desirable,  that  so  far  as  possible, 
a  definition  be  given  in  explicit  terms  as  to  the  basis  and  method  employed 
in  arriving  at  the  percentage.     The  actual  measurement  of  a  sample  of 
soot  and  smoke  by  some  form  of  meter  is  to  be  preferred. 

XX.  MISCELLANEOUS — In  tests  for  purposes  of  scientific  research,  in 
which  the   determination  of  all  the  valuables  entering  into   the   test  is 
desired,    certain     observations     should     be     made     which     are    in     general 
unnecessary  for  ordinary  tests.     These  are  the  measurements  of  the  air 
supply,  the   determination   of   its   contained  moisture,  the   determination 
of   the  amount   of   heat   lost   by   radiation,    of  the   amount   of   infiltration 
of  air  through  the  setting,  and  (by  condensation  of  all  the  steam  made 
by  the  boiler)   of  the  total  heat  imparted  to  the  water. 

As  these  determinations  are  rarely  undertaken,  it  is  not  deemed 
advisable  to  give  directions  for  making  them. 

55 


XXI.  CALCULATIONS  OF  EFFICIENCY — Two  methods  of  defining  and  cal- 
culating the  efficiency  of  a  boiler  are  recommended.    They  are: 

1.  Efficiency  of  the  boiler 

_Heat  absorbed  per  Ib.  combustible 
"Caloric  value  of  1  Ib.  combustible. 

2.  Efficiency  of  the  boiler  and  grate 

_Heat  absorbed  per  Ib.  coal 
""Caloric  value  of  1  Ib.  coal. 

The  first  of  these  is  sometimes  called  the  efficiency  based  on  combus- 
tible, and  the  second  efficiency  based  on  coal.  The  first  is  recommended 
as  a  standard  of  comparison  for  all  tests,  and  this  is  the  one  which  is 
understood  to  be  referred  to  when  the  word  "efficiency"  alone  is  used 
without  qualification.  The  second,  however,  should  be  included  in  a  report 
cf  a  test,  together  with  the  first,  whenever  the  object  of  the  test  is  to  deter- 
mine the  efficiency  of  the  boiler  and  the  furnace  together  with  the  grate  (or 
mechanical  stoker),  or  to  compare  different  furnaces,  grates,  fuels  or  methods 
of  firing. 

The  heat  absorbed  per  pound  of  combustible  (or  per  pound  of  coal) 
is  to  be  calculated  by  multiplying  the  equivalent  evaporation  from  and 
at  212  degrees  per  pound  combustible  (or  coal)  by  965.7. 

XXII.  THE  HEAT  BALANCE — An  approximate  "heat  balance,"  or  state 
ment   of  the   distribution   of   the   heating  value   of  the   coal  among  the 
several  items  of  heat  utilized  and  heat  lost  may  be  included  in  the  report 
of  a  test  when  analyses  of  the  fuel  and  of  the  chimney-gases  have  been 
made.    The  methods  of  computing  the  heat  balance  and  the  form  in  which 
it  should  be  reported,  are  given  in  chapter  on  Steam  Boiler  Efficiency. 

XXIII.  REPORT  OF  THE  TRIAL — The  data  and  results  should  be  reported 
in  the  manner  given  in  either  one  of  the  two  following  tables,  omitting 
lines  where  the  tests  have  not  been  made  as  elaborately  as  provided  for  in 
such   tables.     Additional   lines  may  be   added  for   data  relating     to  the 
specific  object  of  the  test.    The  extra  lines  should  be  classified  under  the 
headings  provided  in  the    tables,  and    numbered    as    per    preceding    line, 
with  sub-letters  a,  ~b,  etc.     The  Short  Form  of  Eeports  is  recommended 
for  commercial   tests   and   as  a  convenient   form   of   abridging   the   longer 
form  of  publication  when  saving  space  is  desirable.    For  elaborate  trials, 
it  is  recommended  that  the  full  log  of  the  trial  be  shown  graphically,  by 
means  of  a  chart. 

DATA  AND  RESULTS  OF  EVAPORATIVE  TEST. 

Made  by of boiler  at to 

determine    

Principal  conditions  governing  the  trial 

Kind  of  fuel. 

Kind  of  furnace 

State  of  the  weather   

Method  of  starting  and  stopping  the  test  ("standard"  or  "alternate," 
Art.  X  and  XI,  Code) 

1.  Date  of  trial 

2.  Duration  of  trial hours. 

Dimensions  and  Proportions. 

(A  complete  description  of  the  boiler,  and  drawings  of  the  same  if  of 
unusual  type,  should  be  given  on  an  annexed  sheet.) 

3.  Grate  surface width length area sq.  ft. 

4.  Height  of  furnace ins 

5.  Approximate  width  of  air  spaces  in  grate in. 

56 


6.  Proportion  of  air  space  to  whole  grate  surface per  cent. 

7.  Water-heating  surface sq.  ft. 

8.  Superheating  surface sq.  ft. 

9.  Ratio  of  water-heating  surface  to  grate  surface — to  1. 

10.  Ratio  of  minimum  draft  area  to  grate  surface 1  to  . 

Average  Pressures. 

11.  Steam  pressure  by  gauge Ibs.  per  sq.  in. 

12.  Draft  between  damper  and  boiler ins.  of  water 

13.  Force  of  draft  in  furnace ins.  of  water 

14.  Force  of  draft  or  blast  in  ash-pit ins.  of  water 

Average  Temperatures. 

1 5.  Of  external  air deg. 

16.  Of  fireroom  deg. 

17.  Of  steam  deg. 

18.  Of  feed  water  entering  heater deg. 

19.  Of  feed  water  entering  economizer deg. 

20.  Of  feed  water  entering  "boiler deg. 

21.  Of  escaping  gases  from  boiler deg. 

22.  Of  escaping  gases  from  economizer deg. 

Fuel. 

23.  Size  and  condition 

24.  Weight  of  wood  used  in  lighting  fire Ibs. 

25.  Weight  of  coal  as  fired Ibs. 

26.  Percentage  of  moisture  in  coal per  cent. 

27.  Total  weight  of  dry  coal  consumed Ibs. 

28.  Total  ash  and  refuse 

29.  Quality  of  ash  and  refuse 

30.  Total  combustible  consumed lb». 

31.  Percentage  of  ash  and  refuse  in  dry  coal per  cent. 

Proximate  Analysis  of  Coal. 

Coal.      Combustible. 

32.  Fixed  carbon   per  cent.         per  cent. 

33.  Volatile  matter   ' '  ' ' 

34.  Moisture    " 

35.  Ash    .  "  


100  %  100  % 

36.  Sulphur,  separately  determined "  " 

Ultimate  Analysis  of  Dry  Coal. 

(Art.  XVII.,  Code.) 

Coal.      Combustible. 

37.  Carbon  (C)    per  cent         per  cent. 

38.  Hydrogen  (H)    

39.  Oxygen  (0)   

40.  Nitrogen   (N)    

41.  Sulphur   (S)    

42.  Ash    . 


100  %  100  % 

43.     Moisture  in  sample  of  coal  as  received —    "  —  " 

57 


Analysis  of  Ash  and  Refuse. 

44.  Carbon per  cent. 

45.  Earthy  matter per  cent. 

Fuel  per  Hour. 

46.  Dry  coal  consumed  per  hour Ibs. 

47.  Combustible  consumed  per  hour Ibs. 

48.  Dry  coal  per  sq.  .'£.  of  grate  surface  per  hour Ibs. 

49.  Combustible  per  square  foot  of  water  heating  surface  per  hour Ibs. 

Calorific  Value  of  Fuel. 
(Art.  XVII.,  Code.) 

50.  Calorific  value  by  oxygen  calorimeter,  per  Ib.  of  dry  coal B.  T.  U. 

51.  Calorific  value  by  oxygen  calorimeter,  per  Ib.  of  combustible.  .  .B.  T.  U. 

52.  Calorific  value  by  analysis,  per  Ib.  of  dry  coal B.  T.  U. 

53.  Calorific  value  by  analysis,  per  Ib.  of  combustible B.  T.  U. 

Quality  of  Steam. 

54.  Percentage  of  moisture  in  steam per  cent. 

55.  Number  of  degrees  of  superheating deg. 

56.  Quality  of  steam   (dry  steam=unity) 

Water. 

57.  Total  weight  of  water  fed  to  boiler Ibs. 

58.  Equivalent  water  fed  to  boiler  from  and  at  212  degrees Ibs. 

59.  Water  actually  evaporated,  corrected  for  quality  of  steam Ibs. 

60.  Factor  of  evaporation Ibs. 

61.  Equivalent  water  evaporated  into  dry  steam  from  and  at  212  de- 

grees.    (Item  59Xltem  60.)    Ibs. 

Water  per  Hour. 

62.  Water  evaporated  per  hour,  corrected  for  quality  of  steam Ibs. 

63.  Equivalent  evaporation  per  hour  from  and  at  212  degrees Ibs. 

64.  Equivalent  evaporation  per  hour  from  and  at  212  degrees  per  square 

foot  of  water  heating  surface Ibs. 

Rorsc-Poiver. 

65.  Horse-Power  developed   (34%  Ibs.  of  water  evaporated  per  hour 

into  dry  steam  from  and  at  212  degrees,  equals  one  horse-power)!^..  P. 

66.  Builders '  rated  horse-power H.  P. 

67.  Percentage  of  builders'  rated  horse-power  developed per  cent. 

Economic  Results. 

68.  Water  apparently  evaporated  under  actual  conditions  per  pound  of 

coal  as  fired.     (Item  57^-Item  25.) Ibs. 

69.  Equivalent  evaporation  from  and  at  212  degrees  per  pound  of  coal 

as  fixed.     (Item  61+Item  25) .Ibs. 

70.  Equivalent  evaporation  from  and  at  212  degrees  per  pound  of  dry 

coal.     (Item  61+Item  27.) Ibs. 

71.  Equivalent   evaporation  from  and  at   212  degrees  per  pound  of 

combustible.     (Item  61+Item  30.) Ibs. 

(If  the  equivalent  evaporation,  Items  69,   70  and  71,  is  not 
corrected  for  the  quality  of  steam,  the  fact  should  be  stated.) 

58 


Efficiency. 
(Art.  XXI.,  Code.) 

72.  Efficiency  of  boiler;  heat  absorbed  by  the  boiler  per  Ib.  of  com- 

bustible divided  by  the  heat  value  of  one  Ib.  of  combustible,  .per  cent. 

73.  Efficiency  of   boiler,  including   the  grate;   heat   absorbed  by   the 

boiler,  per  Ib.  of  dry  coal,  divided  by  the  heat  value  of  one  Ib. 

of  dry  coal per  cent. 

Cost  of  Evaporation. 

74.  Cost  of  coal  per  ton  of Ibs.  delivered  in  boiler  room $.  . .  . 

75.  Cost  of  fuel  for  evaporating  1,000  Ibs.  of  water  under  observed 

conditions  $ .... 

76.  Cost  of  fuel  used  for  evaporating  1,000  Ibs.  water  from  and  at 

212  degrees  $.  . .  . 

Smolce  Observations. 

77.  Percentage  of  smoke  as  observed per  cent. 

78.  Weight  of  soot  per  hour  obtained  from  smoke  meter ounces. 

79.  Volume  of  soot  per  hour  obtained  from  smoke  meter cub.  in. 

Methods  of  Firing. 

80.  Kind  of  firing  (spreading,  alternate  or  coking) 

81.  Average  thickness  of  fire 

82.  Average  intervals  between  firing  for  each  furnace   during   time 

when  fires  are  in  normal  condition 

83.  Average  interval  between  times  of  leveling  or  breaking  up 

Analysis  of  the  Dry  Gases. 

84.  Carbon  dioxide   (CO2) per  cent. 

85.  Oxygen   (O)   " 

86.  Carbon  monoxide  (CO) " 

87.  Hydrogen  and  hydrocarbons " 

.88.  Nitrogen  (by  difference)    (N) " 

100  per  cent. 


59 


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APPROXIMATE   HEATING  VALUE    OP  GENERAL  GRADES  OP 
COAL  PER  POUND  OP  COMBUSTIBLE  B.  T.  U. 


KIND  OF  COAL. 

PER  CENT.  OF  COMBUSTIBLE. 

HEATING  VALUE 
PER  POUND  OF 
COMBUSTIBLE. 

FIXBD  CARBON. 

VOLATILE 
MATTER. 

Anthracite  . 

97.0  to  92.  5 
92.  5  to  87.  5 
87.  5  to  75. 
75.    to  60. 
65.    to  50. 
Under  50. 

3.0to    7.5 
7.  5  to  12.  5 
12.  5  to  25. 
25.    to  40. 
35.    to  50. 
Over     50. 

14,600  to  14,800 
14,700  to  15,500 
15,500  to  16,000 
14,800  to  16,200 
18,500  to  14,800 
11,000  to  1.8  500 

Semi-anthracite  
Semi-bituminous 

Bituminous,  Eastern  

Bituminous,  Western  
Lignite                   

STEAM  DISCHARGES. 


Absolute  Ini- 
tial Pressure 
per  Square 
Inch.  Pounds. 

Velocity  of 
Outflow  at 
Constant  Den- 
sity, Feet  per 
Second.* 

Actual  Veloc- 
ity of  Outflow, 
Expanded. 
Feet  per 
Second. 

Discharge  per 
Square  Inch 
of  Orifice  per 
Minute. 
Pounds. 

Horse-Power 
per  Square  Inch 
of  Orifice  if  H. 
P.  =  80  Ibs. 
per  hour. 

25.37 

863 

1,401 

22.81 

45.6 

30. 

867 

1,408 

26.84 

53.7 

40. 

874 

1,419 

35.18 

70.4 

50. 

880 

1,429 

44.06 

88.1 

60. 

885 

1,437 

52.59 

105.2 

70. 

889 

1,444 

61.07 

122.1 

75.  ' 

891 

1,447 

65.30 

130.6 

90. 

895 

1,454 

77.94 

155.9 

100. 

898 

1,459 

86.34 

172.7 

115. 

902 

1,466 

98.76 

197.5 

135. 

906 

1,472 

115.61 

231.2 

155. 

910 

1,478 

132.21 

264.4 

165. 

912 

1,481 

140.46 

280.9 

215. 

919 

1,493 

181.58 

.363.2 

COMPARISON  OF  OIL  AND  COAL. 


B.  T.  U.  Per  Pound 
of  Coal. 

Pounds  of  Coal  Equal 
to  One  Barrel 
of  Oil. 

Barrels  of  Oil  Equal 
to  One  Short  Ton 
of  Coal. 

10,000 
11,000 
12,000 
13,000 
14,000 
15,000 

620 
564 
517 
477 
443 
413 

8.23 
3.55 

3.87 
4.19 
4.52 

4.84 

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TABLE  OF  PROPERTIES  OF  SATURATED  STEAM. 


Total 
Pres- 
sure 
perSq 
Inch. 

Tempera- 
ture in 
Fahrenh't 
Degrees. 

Total  Heat 
in  Heat 
Units  from 
Water  at 
32°  Fahr. 

Latent 
Heat 
in 
Heat 
Units 

Density 
Weight  of 
Cubic  Foot 

Volume  ol 
One 
Pound  of 
Steam. 

Relative 
Volume, 
or  Cub.  Ft. 
from  One 
of  Water. 

Factor  of 
Equiva- 
lent Evap- 
oration, at 
812°. 

1 

102 

1113.05 

1042.964 

.0030 

330.36 

•0620 

0.965 

2 

126.266 

1120.45 

1026.010 

.0058 

172.08 

107*0 

0.972 

3 

141.622 

1125.131 

1015.254 

.0085 

117.52 

7326 

0.977 

4 

158.070 

1128.625 

1007.229 

.0112 

89.62 

5600 

0.981 

5 

162.830 

1131.449 

1000.727 

.0137 

72.66 

4535 

0.984 

6 

170.123 

1133.826 

995.219 

.0163 

61.21 

3814 

0.986 

7 

176.910 

1135.896 

990.471 

.0189 

52.94 

3300 

0.988 

8 

182.910 

1137.726 

986.245 

.0214 

46.69 

2910 

0.990 

9 

188.316 

1139.375 

982.434 

.0239 

41.79 

2607 

0.992 

10 

193.240 

1140.877 

978.958 

.0264 

37.84 

2360 

0.994 

15 

213.025 

1146.912 

964.973 

.0387 

25.85 

1612 

1.000 

20 

227.917 

1151.454 

954.415 

.0511 

19.72 

1220.3 

1.005 

25 

240.000 

1155.139 

945.825 

.0634 

15.99 

984.8 

1.008 

30 

250.245 

1158.263 

938.925 

.0755 

13.46 

826.8 

1.012 

35 

259.176 

1160.987 

932.152 

.0875 

11.85 

713.4 

1.015 

40 

267.120 

1163.410 

926.472 

.0994 

10.27 

628.2 

1.017 

45 

274.296 

1165.600 

921.334 

.1111 

9.18 

561.8 

1.019 

50 

280.854 

1167.600 

916.631 

.1227 

8.31 

508.5 

1.021 

55 

286.897 

1169.442 

912.290 

.1343 

7.61 

464.7 

1.023 

60 

292.520 

1171.158 

908.247 

.1457 

7.01 

428.5 

1.025 

65 

297.777 

1172.762 

904.462 

.1569 

6.49 

397.7 

1.027 

70 

302.718 

1174.269 

900.899 

.1681 

6.07 

871.2 

1.028 

75 

307.388 

1175.692 

897.526 

.1792 

5.68 

348.3 

1.030 

80 

311.812 

1177.042 

894.830 

.1901 

5.35 

328.3 

1.031 

85 

316.021 

1178.326 

891.286 

.2010 

5.05 

810.5 

1.033 

90 

320.039 

1179.551 

8S8.375 

.2118 

4.79 

294.7 

1.034 

95 

323.884 

1180.724 

885.588 

.2234 

4.55 

280.6 

1.035 

100 

327.571 

1181.849 

883.914 

.2330 

4.33 

267.9 

1.036 

105 

331.113 

1182.929    880.342 

.2434 

4.14 

265.5 

1.037 

110 

334.523 

1183.970   877.865 

.2537 

3.97 

246.0 

1.038 

115 

337.814 

1184.974    875.472 

.2640 

3.80 

236.3 

1.039 

120 

340.995 

1185.944 

873.155 

.2742 

3.65 

227.6 

1.040 

125 

344.074 

1186.883 

870.911 

.2842 

3.51 

219.7 

1.041 

130 

347.059 

1187.794 

868.735 

.2942 

3.38 

212.3 

1.042 

140 

352.757 

1189.535 

864.566 

.3138 

3.16 

199.0 

1.044 

150 

358.161 

1191.180 

860.621 

.3340 

2.96 

187.5 

1.046 

160 

868.277 

1192.741 

856.874 

.3520 

2.79 

177.3 

1.047 

170 

368.158 

1194.228 

853.294 

.3709 

2.fi3 

168.4 

1.049 

180 

872.822 

1195.650 

849.869 

.3889 

2.49 

160.4 

1.051 

190 

377.291 

1197.013 

846.584 

.4072 

2.37 

153.4 

1.052 

200 

381.573 

1198.310 

843.432 

.4249 

2.26 

147.1 

1.053 

250 

401.072 

1203.735 

831.222 

.5464 

1.83 

114 

1.059 

300 

418.225 

1208.737 

819.610 

.6486 

1.54 

96 

1.064 

350 

431.956 

1212.580 

810.690 

.7498 

1.33 

83 

1.068 

400 

444.919 

1217.094 

800.198 

.8502 

1.18 

73 

1.073 

I 

PROPERTIES  OF  SATURATED  STEAM. 


Pressure 
above 
Vacuum. 
Lbs.  per 
Sq.  Inch. 

Temperature 
Degrees 
Fahrenheit. 

Heat  of  Liquid 
above  32° 
Fahrenheit. 
B.  T.  U. 

Latent  Heat 
above  32° 
Fahrenheit 
B.  T.  U. 

Total  Heat 
above  32° 
Fahrenheit. 
B.  T.  U. 

Density,  or 
Weight  per 
Cubic  Foot. 
Pounds. 

2 

126.3 

94.4 

1026.1 

1120.5 

0.00576 

4 

153.1 

121.4 

1007.2 

1128.6 

0.01107 

6 

170.1 

138.6 

995.2 

1133.8 

0.01622 

8 

182.9 

151.5 

986.2 

1137.7 

0.02125 

10 

193.3 

161.9 

979.0 

1140.9 

0.02621 

12 

202.0 

170.7 

972.9 

1143.6 

0.03111 

14 

209.6 

178.3 

967.5 

1145.8 

0.03600 

14.7 

212.0 

180.8 

965.8 

1146.6 

0.03760 

16 

216.3 

185.1 

962.8 

1147.9 

0.04067 

18 

222.4 

191.3 

958.5 

1149.8 

0.04547 

20 

228.0 

196.9 

954.6 

1151.5 

0.05023 

22 

233.1 

202.0 

951.0 

1153.0 

0.05495 

24 

237.8 

206.8 

947.6 

1154.4 

0.05966 

26 

242.2 

211.2 

944.6 

1155.8 

0.06432 

28 

246.4 

215.4 

941.7 

1157.1 

,0.06899 

30 

250.3 

219.4 

938.9 

1158.3 

0.07360 

32 

254.0 

223.1 

936.3 

1159.4 

0.07821 

34 

857.5 

226.7 

933.7 

1160.4 

0.08280 

36 

260.9 

230.0 

931.5 

1161.5 

0.08736 

38 

264.1 

233.3 

929.2 

1162.5 

0.09191 

40 

267.1 

236.4 

927.0 

1163.4 

0.09644 

42 

270.1 

239.3 

925.0 

1164.3 

0.1009 

44 

272.9 

242.2 

923.0 

1165.2 

0.1054 

46 

275.7 

245.0 

921.0 

1166.0 

0.1099 

48 

278.3 

247.6 

919.2 

1166.8 

0.1144 

60 

280.9 

250.2 

917.4 

1167.6 

0.1188 

52 

283.3 

252.7 

915.7 

1168.4 

0.1233 

54 

285.7 

255.1 

914.0 

1169.1 

0.1277 

56 

288.1 

257.5 

912.3 

1169.8 

0.1321 

58 

290.3 

259.7 

910.8 

1170.5 

0.1366 

60 

292.5 

261.9 

909.3 

1171.2 

0.1409 

62 

294.7 

264.1 

907.7 

1171.8 

0.1453 

64 

296.7 

266.2 

906.2 

1172.4 

0.1497 

66 

298.8 

268.3 

904.7 

1173.0 

0.1541 

68 

300.8 

270.3 

903.3 

1173.6 

0.1584 

70 

302.7 

272.2 

902.1 

1174.8 

0.1628 

72 

304.6 

274.1 

900.8 

1174.9 

0.1671 

74 

306.5 

276.0 

899.4 

1175.4 

0.1714 

76 

308.3 

277.8 

898.2 

1176.0 

0.1757 

78 

310.1 

279.6 

896.9 

1176.5 

0.1801 

80 

311.8 

281.4 

895.6 

1177.0 

0.1843 

82 

313.5 

283.2 

894.4 

1177.6 

0.1886 

84 

315.2 

285.0 

893.1 

1178.1 

0.1930 

86 

316.8 

286.7 

891.9 

1178.6 

0.1978 

88 

318.5 

288.4 

890.7 

1179.1 

0.2016 

90 

320.0 

290.0 

889.6 

1179.6 

O.S058 

92 

321.6 

291.6 

888.4 

1180.0 

0.2101 

94 

323.1 

293.2 

887.3 

1180.5 

0.2144 

96 

324.6 

294.8 

886.2 

1181.0 

0.2186 

98 

326.1 

296.4 

885.0 

1181.4 

0.2229 

100 

827.6 

297.9 

884.0 

1181.9 

0.2271 

102 

329.0 

299.4 

882.9 

1182.8 

0.2314 

104 

330.4 

300.9 

881.8 

1182.7 

0.2356 

67 


PROPERTIES  OP  SATURATED  STEAM— (Continued). 


Pressure 
above 
Vacuum 
Lbs.  per 
Sq.  Inch. 

Temperature, 
Degrees 
Fahrenheit. 

Heat  of  Liquid 
above  32° 
Fahrenheit. 
B.  T.  U. 

Latent  Heat 
above  32° 
Fahrenheit 
B.  T.  U. 

Total  Heat 
above  32° 
Fahrenheit. 
B.  T.  U. 

Density,  or 
Weight  per 
Cubic  Foot. 
Pounds. 

106 

831.8 

302.3 

880.8 

1183.1 

0.2399 

108 

333.2 

303.8 

879.8 

1183.6 

0.2441 

110 

334.6 

805.2 

878.8 

1184.0 

0.2484 

112 

335.9 

306.6 

877.8 

1184.4 

0.2526 

114 

337.2 

308.0 

876.8 

1184.8 

0.2568 

116 

338.5 

309.4 

875.8 

1185.2 

0.2610 

118 

339.8 

810.7 

874.9 

1185.6 

0.2653 

120 

841.1 

312.0 

874.0 

1186.0 

0.^695 

122 

342.3 

813.3 

873.0 

1186.3 

0.2786 

124 

343.5 

314.6 

872.1 

1186.7 

0.2779 

126 

344.7 

815.9 

871.2 

1187.1 

0.2820 

128 

345.9 

317.1 

870.3 

1187.4 

0.2862 

130 

347.1 

818.4 

869.4 

1187.8 

0.2904 

132 

348.3 

319.6 

868.6 

1188.2 

0.2946 

134 

349.5 

320.8 

867.7 

1188.5 

0.2988 

136 

350.6 

322.0 

866.9 

1188.9 

0.3030 

138 

351.7 

223.2 

866.0 

1189.2 

0.8072 

140 

352.9 

324.4 

865.1 

1189.5 

0.3113 

142 

354.0 

325.6 

864.3 

1189.9 

0.3155 

144 

355.1 

326.7 

863.5 

1190.2 

0.3197 

146 

356.1 

327.8 

862.8 

1190.6 

0.3239 

148 

357.2 

328.9 

862.0 

1190.9 

0.3280 

150 

358.3 

330.0 

861.2 

1191.2 

0.3321 

152 

359.3 

331.1 

860.4 

1191.5 

0.3363 

154 

360.3 

332.2 

859.6 

1191.8 

0.3405 

156 

361.4 

333.3 

858.9 

1192.2 

0.3447 

158 

362.4 

334.3 

858.2 

1102.5 

0.3488 

160 

363.4 

835.4 

857.4 

1192.8 

0.3530 

162 

364.4 

336.4 

856.7 

1193.1 

0.3572 

164 

365.4 

337.5 

855.9 

1193.4 

0.8614 

166 

366.4 

338.5 

855.2 

1143.7 

0.3655 

168 

367.3 

339.5 

854.5 

1194.0 

0.3695 

170 

368.3 

340.5 

853.8 

1194.3 

0.3737 

172 

369.2 

841.5 

853.1 

1194.6 

0.3778 

174 

370.2 

842.5 

852.3 

1194.8 

0.3820 

176 

371.1 

343.5 

851.6 

1195.1 

0.8862 

178 

372.1 

344.4 

851.0 

1195.4 

0.3904 

180 

373.0 

345.4 

850.3 

1195.7 

0.3945 

183 

373.9 

346.4 

849.6 

1196.0 

0.3987 

184 

374.8 

347.3 

848.9 

1196.2 

0.4029 

186 

875.7 

348.2 

848.3 

1196.5 

0.4070 

188 

376.6 

349.2 

847.6 

1196.8 

0.4111 

190 

377.4 

350.1 

847.0 

1197.1 

0.4158 

192 

378.3 

851.0 

846.3 

1197.3 

0.4194 

194 

379.9 

351.9 

845.7 

1197.6 

0.4236 

196 

380.0 

352.8 

845.0 

1197.8 

0.4278 

198 

380.9 

353.7 

844.4 

1198.1 

0.4318 

200 

381.7 

854.6 

843.8 

1198.4 

0.4359 

202 

382.6 

855.4 

843.2 

1198.6 

0.4399 

204 

383.4 

356.3 

842.6 

1198.9 

0.4441 

206 

884.2 

857.2 

841.9 

1199.1 

0.4482 

208 

385.1 

358.0 

841.4 

1199.4 

0.4524 

210 

385.9 

858.9              840.7 

1199.6 

0.4565 

PROPERTIES  OP  SATURATED  STEAM— (Continued). 


Pressure 
above 
Vacuum 
Lbs.  per 
Sq.  Inch. 

Temperature, 
Degrees 
Fahrenheit. 

Heat  of  Liquid 
above  32° 
Fahrenheit. 
B.  T.  U. 

Latent  Heat 
above  32° 
Fahrenheit. 
B.  T.  U. 

Total  Heat 
above  32° 
Fahrenheit. 
B.  T.  U. 

Density,  or 
Weight  per 
Cubic  Foot. 
Pounds. 

212 

386.7 

359.7 

840.2 

1199.9 

0.4607 

214 

387.5 

360.6 

839.5 

1200.1 

0.4648 

216 

888.3 

361.4 

839.0 

1200.4 

0.4690 

218 

389.1 

362.2 

838.4 

1200.6 

0.4781 

220 

389.8 

363.0 

837.8 

1200.8 

0.4772 

222 

390.6 

863.9 

837.2 

1201.1 

0.4813 

224 

391.4 

864.7 

836.6 

1201.3 

0.4855 

226 

392.2 

365.5 

836.1 

1201.6 

0.4896 

228 

392.9 

366.3 

835.5 

1201.8 

0.4989 

230 

393.7 

367.1 

834.9 

1202.0 

0.4979 

232 

394.5 

367.9 

834.3 

1202.2 

0.5021 

234 

395.2 

368.6 

833.9 

1202.5 

0.5062 

236 

395.9 

369.4 

833.3 

1202.7 

0.5103 

238 

396.7 

870.2 

832.7 

1202.9 

0.5144 

240 

397.4 

371.0 

832.2 

1203.2 

0.5186 

242 

398.1 

371.7 

831.7 

1203.4 

0.5226 

244 

898.9 

872.5 

831.1 

1203.6 

0.5268 

246 

899.6 

873.2 

830.6 

1203.8 

0.5311 

248 

400.3 

374.0 

830.0 

1204.0 

0.5353 

250 

401.0 

374.7 

829.5 

1204.2 

0.5393 

252 

401.7 

375.4 

829.1 

1204.5 

0.5483 

254 

402.4 

876.2 

828.5 

1204.7 

0.5475 

256 

403.1 

876.9 

828.0 

1204.9 

0.5517 

258 

403.8 

377.6 

827.5 

1205.1 

0.5559 

260 

404.5 

378.4 

826.9 

1205.3 

0.5601 

262 

405.2 

379.1 

826.4 

1205.5 

0.5642 

264 

405.8 

379.8 

825.9 

1205.7 

0.5684 

266 

406.5 

380.5 

825.4 

1205.9 

0.5726 

268 

407.2 

381.2 

824.9 

1206.1 

0.5767 

270 

407.9 

381.9 

824.4 

1206.3 

0.5809 

272 

408.6 

882.6 

823.9 

1206.5 

0.5850 

274 

409.2 

383.3 

823.4 

1206.7 

0.5892 

276 

409.8 

384.0 

822.9 

1206.9 

0.5934 

278 

410.5 

384.6 

822.5 

1207.1 

0.5976 

280 

411.1 

385.3 

822.0 

1207.3 

0.602 

282 

411.8 

886.0 

821.5 

1207.6 

0.606 

284 

412.4 

b86.6 

821.1 

1207.7 

0.610 

286 

413.0 

887.3 

820.6 

1207.9 

0.614 

288 

413.7 

388.0 

820.1 

1208.1 

0.618 

290 

414.3 

888.6 

819.7 

1208.3 

0.622 

292 

414.9 

389.3 

819.2 

1208.6 

0.627 

294 

415.6 

390.0 

818.7 

1208.7 

0.631 

296 

416.2 

390.6 

818.3 

1208.9 

0.635 

298 

416.8 

391.3 

817.8 

1209.1 

0.639 

300 

417.4 

891.9 

817.4 

1209.3 

0.644 

302 

418.0 

392.5 

816.9 

1209.4 

0.648 

304 

418.6 

393.2 

816.4 

1209.6 

0.65J 

306 

419.2 

393.8 

816.0 

1209.8 

0.656 

308 

419.8 

394.4 

815.6 

1210.0 

0.660 

310 

420.4 

395.0 

815.2 

1210.2 

0.664 

312 

421.0 

895.7 

814.7 

1210.4 

0.668 

314 

421.6 

396.3 

814.2 

1210.5 

0.673 

316 

422.2 

396.9 

813.8 

1210.7 

0.677 

PROPERTIES  OP  SATURATED  STEAM— (Continued). 


Pressure 
above 
Vacuum 
Lbs.  per 
Sq.  Inch. 

Temperature, 
Degrees 
Fahrenheit. 

Heat  of  Liquid 
above  32° 
Fahrenheit. 
B.  T.  U. 

Latent  Heat 
above  32° 
Fahrenheit, 
B.  T.  U. 

Total  Heat 
above  32° 
Fahrenheit. 
B.  T.  U. 

Density,  or 
Weight  per 
Cubic  Foot. 
Pounds. 

318 

422.8 

397.5 

813.4 

1210.9 

0.681 

320 

423.4 

398.1 

813.0 

1211.1 

0.685 

322 

424.0 

398.7 

812.5 

1211.2 

0.690 

324 

424.5 

399.3 

812.1 

1211.4 

0.694 

326 

425.1 

899.9 

811.7 

1211.6 

0.698 

328 

425.7 

400.5 

811.3 

1211.8 

0.702 

330 

4-26.2 

401.1 

810.8 

1211.9 

0.707 

335 

427.6 

402.6 

809.8 

1212.4 

0.717 

350 

431.9 

406.9 

806.8 

1213.7 

0.748 

375 

438.4 

414.2 

801.5 

1215.7 

0.800 

400 

445.2 

421.4 

796.3 

1217.7 

0.853 

450 

456.  ^ 

433.4 

787.7 

1221.1 

0.959 

500 

466.6 

444.3 

779.9 

1224.2 

1.065 

AIR  REQUIRED  FOR  VENTILATION. 


Standard  Parts  of  Carbonic  Acid 

Cubic  Feet  of  Air  Required,  per  Person. 

Per  Minute. 

Per  Hour, 

5 

133 

8,000 

6 

67 

4,000 

7 

44 

2,667 

8 

33 

2,020 

9 

27 

1,600 

10 

22 

1,333 

11 

19 

],151 

12 

17 

1,000 

VENTILATION  FOR  DIFFERENT  TYPES  OF  BUILDINGS. 


Air  Supply  per  Occupant  for 

Cubic  Feet  per 
Minute. 

Cubic  Feet  per 
Hour. 

Hospitals         .... 

50  to  80 

3,000  to  4,000 

High  Schools 

50 

3,000 

Grammar  Schools  
Theatres  and  Assembly  Halls  
Churches 

40 
25 
20 

2,400 
1,500 
1  200 

HORSE  POWER  FOR  VENTILATION. 

Our  B.  T.  U.  will  raise  the  temperature  of  one  cubic  foot  of  air  55 
degrees.  In  other  words,  the  B.  T.  U.  required  to  raise  any  given  volume 
of  air  any  number  of  degrees  is  equal  to  : 

Volume  of  Air  in  Cubic  Feet  x  Degrees  T?aised 
55 


7U 


VELOCITIES    OBTAINED  THROUGH    FLUES    OP   HEIGHTS    FOR 

VARYING  DIFFERENCES  IN  TEMPERATURE  BETWEEN 

OUTSIDE  AIR  AND  THAT  IN  FLUE. 


Excess  of  Temperature  of  Air  in  Flue  Above  that  of  External  Air. 

Height  of  Flue 
in  Feet. 

5° 

10° 

15° 

20° 

30° 

50° 

5 

55 

70 

94      109 

134 

167 

10 

77 

108 

133 

153 

188 

242 

15 

94 

133 

162 

1»8 

230 

297 

20 

108 

153 

188 

217 

225 

342 

25 

121 

171 

210 

242 

297 

383 

30 

133 

188 

230 

265 

325 

419 

35 

1-13 

203 

248 

286 

351 

458 

40 

153 

217 

265 

306 

375 

484 

45 

162 

230 

282 

325 

398 

514 

50 

171 

242 

297 

342 

419 

541 

GO 

188 

264 

325 

378 

461 

594 

NUMBER    OF    SQUARE    FEET    OF    DIRECT   STEAM    RADIATION 

DIFFERENT  SIZES  OF  PIPES  WILL  SUPPLY  FOR 

VARYING  LENGTHS  OF  RIM. 

Square  Feet  of  Radiating  Surface. 


Size  of  Pipe. 

100  ft. 
Rim. 

200ft. 
Riui. 

300ft. 
Rim. 

400ft. 
Rim. 

500ft. 
Rim. 

600ft. 
Rim. 

700ft. 
Rim. 

800ft. 
Rim. 

900ft. 
R  m. 

1 

30 

\\A 

60 

50 

Ii2 

100 

75 

50 

2 

200 

150 

125 

100 

7.1 

2V£ 

850 

250 

200 

175 

150 

125 

8 

3^ 

5 
6 

7 

550 
850 
1200 

400 
600 
850 
1400 

300 
450 
700 
1150 

275 
400 
600 
1000 
1600 

250 
350 
525 
700 
1400 

225 
325 
475 
850 
1300 

200 
300 
450 
775 
1-200 
1700 

175 
250 
400 
725 
1150 
1606 

150 
22--) 
350 
050 
1000 
1500 

SIZES  FOR  VERTICAL  RISERS  AND  DROPS  FOR 
STEAM  HEATING. 


Square  Feet  of  Radiating  Surface. 


1st  Story. 

2.1  Story. 

3d  Story. 

4th  Story. 

5th  Story. 

6th  Story. 

1 

Ifcl 

¥ 

2M 

30 
60 
100 
200 
350 

55 
90 
140 
275 
475 

65 
110 
165 
375 

75 
125 
185 
4-J5 

85 
140 
210 
500 

95 
160 
240 

3 

550 

3^ 

850 

TONNAGE  BASIS  IN  REFRIGERATING  WORK. 

One  ton  of  refrigeration  is  the  amount  of  heat  absorbed  by  the  melting 
of  2,000  pounds  of  ice  at  32°  F.  into  2,000  pounds  of  water  at  32°  F.,  or  the 
amount  of  heat  that  must  be  extracted  from  2,000  pounds  of  water  at  32°  F. 
to  reduce  it  to  2,000  pounds  of  ice  at  32°  F.,  which  is  2,000X142=284.000 
B.  T.  U.  The  reason  the  multiplier  142  is  used,  is  that  the  latent  heat  of 
one  pound  of  ice  is  142  B.  T.  U. 


COMPRESSION   PLANT   IN  REFRIGERATION 

is  one  where  the  gas  is  drawn  from  the  expansion  side  of  the  plant  by  the 
suction  of  the  compressor,  compressed  to  a  liquifying  pressure  and  dis- 
charged into  the  condenser. 


WITH  THE  ABSORPTION  PLANT 

the  gas  from  the  expansion  side  is  absorbed  into  water  and  a  rich  liquor  so 
made  is  heated  in  a  still,  and  the  ammonia  gas  driven  out  of  the  water  and 
forced  into  the  condenser. 


POWER  REQUIRED  FOR  REFRIGERATING  PLANT 

is,  broadly  speaking,  about  1.5  horse  power  per  ton  of  refrigeration,  for 
plants  above  10  tons;  for  less  tonnage  about  2  horse  power  per  ton  is  allowed. 


TESTING  AND  CHARGING  OF  REFRIGERATING  MACHINERY 

as  given  by  a  prominent  firm  of  builders,  is  as  follows: 

In  testing  a  refrigerating  plant,  it  is  advisable  to  pump  up  an  air  pres- 
sure of  300  pounds  per  square  inch.  A  soap  suds  solution  should  then  be 
applied  to  all  joints  to  detect  any  leakage.  If  leaks  are  discovered,  the  air 
must  be  allowed  to  escape  and  such  new  gaskets  inserted  or  such  new  joints 
made,  as  circumstances  demand. 

After  the  entire  plant  has  been  carefully  examined  and  found  absolutely 
tight,  a  pressure  of  300  pounds  should  be  maintained  and  the  compressor 
permitted  to  remain  idle  for  a  period  of  about  twelve  hours.  Unless  there 
is  further  leakage  or  a  severe  fluctuation  in  atmospheric  temperature,  this 
pressure  will  remain  constant.  When  such  a  condition  is  assured,  it  is  ad- 
visable to  admit  a  small  quantity  of  ammonia  into  the  system.  For  instance, 
a  10-ton  plant  would  require  about  15  pounds,  a  25-ton  plant,  about  30 
pounds,  a  50-ton  plant,  about  60  pounds  by  weight  and  for  a  100-ton  plant, 
about  one  cylinder  of  ammonia  should  be  used. 

A  pressure  of  about  300  pounds  per  square  inch  should  then  be  pumped 
up,  and  in  the  event  of  further  leakage  in  any  part  of  the  plant,  it  will 
readily  be  detected  because  of  the  obnoxious  odor  of  ammonia  gas. 

Several  methods  of  detecting  ammonia  leaks  are  employed,  among  which 
are  the  use  of  litmus  paper,  usually  supplied  by  manufacturers  of  ammonia, 
and  also  by  the  use  of  sulphur  sticks.  White  litmus  paper  slightly  moistened 

72 


will  turn  red  in  the  presence  of  ammonia  fumes.  Lighted  sulphur  sticks, 
when  brought  into  contact  with  the  ammonia  fumes  will  create  a  very  black 
smoke.  This  is  one  of  the  most  positive  methods  known.  After  the  plant 
has  been  tested  in  this  manner,  all  compressed  air  should  be  allowed  to  es- 
cape down  to  the  atmospheric  pressure,  after  which  the  machine  should  be 
started  and  the  coils  evacuated  of  any  remaining  air,  until  there  exists  a 
vacuum  of  from  28  to  29  inches. 

The  machine  should  again  be  permitted  to  stand  inactive  for  a  period  of 
from  six  to  eight  hours  for  the  purpose  of  determining  whether  the  piping 
and  joints  are  absolutely  tight  against  the  external  pressure  of  the  atmos- 
phere. If  the  system  is  tight,  the  vacuum  will  remain  constant.  Should  the 
vacuum  be  broken,  it  will  indicate  the  presence  of  a  leak,  which  should  be 
definitely  located. 

After  the  plant  has  been  finally  tested  with  both  air  pressure  and  vacuum, 
the  system  should  be  pumped  down  to  about  28  or  29  inches  and  the  ammonia 
drums  connected.  The  ammonia  should  be  permitted  to  run  into  the  low  pres- 
sure side  until  a  pressure  of  10  or  15  pounds  is  secured.  The  condensing  water 
must  then  be  supplied  to  ammonia  condenser  and  the  machine  operated  for  the 
purpose  of  confining  the  ammonia  to  the  condenser  and  liquid  receiver.  When 
pumping  the  ammonia  into  the  system,  we  advise  that  the  pressure  on  the  low 
pressure  side  of  the  machine  never  be  decreased  to  the  extent  of  less  than  5 
pounds,  as  the  small  quantity  of  ammonia  then  remaining  in  the  ammonia 
drum  would  not  justify  the  expense  of  pumping  down  to  a  10  or  15-inch  vac- 
uum as  is  frequently  done  for  the  purpose  of  securing  a  complete  evacua- 
tion of  the  drum.  This  is  also  a  doubtful  method  of  charging  the  machine,  ow- 
ing to  the  liability  of  admitting  considerable  air  through  the  stuffing  box 
packing  on  the  piston  rod,  when  working  the  machine  under  a  vacuum.  This 
of  course,  would  create  a  false  condensing  pressure,  which  would  necessitate 
the  interruption  of  the  machine  for  the  purpose  of  purging  the  system. 


73 


PROPERTIES  OP  SATURATED  AMMONIA  GAS. 


Gauge  Pressure 
Pounds 
per  Square  Inch. 

Absolute  Pres- 
sure, Pounds  per 
Square  Inch. 

Temperature 
Degrees  F. 

Absolute  Tem- 
perature Degrees 
Fahrenheit. 

Latent  Heat  of 
Evaporation  In 
Thermal  Units. 

Volume  of  One 
Pound  Vapor  In 
Cubic  Feet. 

Weight  of  One  II 
Cubic  Foot  of 
Vapor  in  pounds,  n 

Volume  of  One 
Pound  of  Liquid 
in  Cubic  Feet. 

Weight  of  One 
Cubic  Foot  of 
Liquid  in  pounds. 

—4.01 

10.69 

-40 

420.66 

579.67 

24.38 

.0410 

.0234 

42.589 

—2.39 

12.31 

-35 

425.66 

576.68 

21.32 

.0469 

.0236 

42.337 

-0.57 

14.13 

-30 

430.66 

573.69 

18.69 

.0535 

.0237 

42.123 

+1.47 

16.17 

-25 

435.66 

570.68 

16.44 

.0608 

.0238 

41.858 

3.75 

18.45 

—20 

440.66 

567.67 

14.51 

.0690 

.0240 

41.615 

6.29 

20.99 

-15 

445.66 

564.64 

12.83 

.0779 

.0241 

41.374 

9.1<> 

23.80 

—10 

450.66 

661.61 

11.38 

.0878 

.0243 

41  .  135 

12.22 

'Z6.92 

—  5 

455.66 

558.56 

10.12 

.0988 

.0244 

40.900 

15.67 

30.37 

0 

460.66 

555.50 

9.03 

.1107 

.0246 

40.650 

19.46 

34.16 

+  5 

465.66 

552.43 

8.07 

.1240 

.0247 

40.404 

23.64 

38.34 

10 

470.66 

549.35 

7.23 

.1383 

.0249 

40.160 

28.24 

42.94 

15 

475.66. 

546.26 

6.49 

.1541 

.0250 

39.920 

33.25 

47.95 

20 

480.66 

543.15 

5.84 

.1711 

.0252 

39.682 

38.73 

53.43 

25 

485.66 

540.03 

5.27 

.1897 

.0253 

39.432 

44.72 

59.42 

30 

490.66 

536.91 

4.76 

.2099 

.0255 

39.200 

51.22 

65.92 

35 

495.66 

533.78 

4.31 

.2318 

.0256 

38.940 

58.29 

72.99 

40 

500.66 

530.63 

3.91 

.2554 

.0258 

38.684 

65.96 

80.66 

45 

505.66 

527.47 

3.56 

.2809 

.0260 

38.461 

74.26 

88.96 

50 

510.66 

524.30 

3.24 

.3084 

.0261 

38.226 

83.22 

97.92 

55 

5J5.66 

521.12 

2.96 

.3380 

.0263 

37.994 

92.89 

107.59 

60 

520.66 

517.93 

2.70 

.3697 

.0265 

37.736 

103.33 

118.03 

65 

525.66 

514.73 

2.48 

.4039 

.0266 

37.481 

114.49 

129.19 

70 

530.66 

511.52 

2.27 

.4401 

.0260 

37.230 

126.52 

141.22 

75 

535.66 

508.29 

2.09 

.4791 

.0270 

36.995 

139.40 

154.10 

80 

540.66 

505.05 

.92 

.5205 

.0272 

36.751 

153.18 

167.88 

85 

545.66 

501.81 

.77 

.5649 

.0273 

36.509 

167.92 

182.62 

90 

550.66 

498.55 

.64 

.6120 

.0275 

36.258 

183.65 

198.35 

95 

555.66 

495.29 

.51 

.6622 

.0277 

36.023 

200.42 

215.12 

100 

560.66 

492.01 

.39 

.7153 

.0279 

35.778 

218.28 

232.98 

105 

565.66 

4*8  .  72 

1.289 

.7757 

.0281 

237.27 

251.97 

110 

570.66 

485.42 

1.203 

.8312 

.0283 

258.7 

272.14 

115 

575.66 

482.41 

1.121 

.8912 

.0285 

275.79 

293.49 

120 

58J.66 

478.79 

1  041 

.9608 

.0287 

301.46 

316.16 

125 

585.66 

475.45 

.9699 

1.0310 

.0289 

325.72 

340.42 

130 

590.66 

472.11 

.9051 

1.1048 

.0291 



350.46 

365.16 

135 

595.66 

468.75 

.8457 

1  .  1824 

.0293 

377.52 

392.22 

140 

600.66 

465.39 

.7910 

1.26421.0295 

405.79 

420.49 

145 

605.66 

462.01 

.7408  1.34971.  0297 

435.5 

450.20 

150 

610.66 

458.62 

.69461.4396  .0299 

466.84 

481.54 

155 

615.66 

455.22 

.65111.5358  .0302 

499.70 

514.50 

160 

620.66 

451.81 

.61  28  1.6318!.  0304 

534.34 

549.04 

165 

625.66 

448.39 

.576511.7344.0306 

One  atmosphere  in  this  table  is  equal  to  a  pressure  of  a  column  of  mercury. 

29.9  inches  high. 
Specific  heat  of  ammonia  gas  and  vapor  at  constant  pressure  =  0.508 

The  same  at  constant  volume =  0.3913 

Weight  of  1  cubic  foot  liquid  ammonia  at  32  degrees  Fahr.  =39.108  Lbs. 

Volume  of  1  pound  liquid  ammonia  at  32  degrees  Fahr =  0.04557  cu.ft. 

Specific  heat  of  liquid  ammonia =  1.01233  +  0.008378  t.« 


TABLE  OF  BRINE  SOLUTION. 

(CHLORIDE  OP  SODIUM— COMMON  SALTS.) 


Percentage 
of  Salt 
by  Weight. 

Degrees  on 
Salometer 
at  60 
Degrees  F. 

o  cs  * 

?*&i 

ijf 

Specific 
Heat. 

Weight  of 
1  Gallon. 

Pounds  of 
Salt  in 
1  Gallon. 

Pounds  of 
Water  in 
l  Gallon. 

+3  r- 
A  W 

•sl 
£Z 

Pounds  of 
Salt  in  1 
Cubic  Foot. 

Pounds  of 
Water  in  1 
Cubic  Foot. 

Freezing 
Point,  De- 
grees Fah. 

0 

0 

i. 

1. 

8.35 

0. 

8.35 

62.4 

0. 

62.4 

32. 

1 

4 

1.C07 

0.992 

8.4 

0.084 

8.316 

62.8 

0.628 

62.172 

31.8 

5 

20 

1.037 

0.96 

8.65 

0.432 

8.218 

64.7 

3.237 

61.465 

25.4 

10 

40 

1.073 

0.892 

8.95 

0.895 

8.055 

66.95 

6.695 

60.253 

18.6 

15 

60 

1.115 

0.855 

9.3 

1.395 

7.905 

69.57 

10.435 

59.134 

12.2 

20 

80 

1.150 

0.829 

9.6 

1.92 

7.68 

71.76 

14.352 

57.408 

6.86 

25 

100 

1.191 

0.783 

9.94 

2.485 

7.455 

74.26 

18.565 

55.695 

1.00 

TABLE  OP  CHLORIDE  OF  CALCIUM  SOLUTION. 


Specific 
Gravity  at  64 
Degrees  Fah. 

Degree 
Beaume  at  64 
Degrees  Fah. 

Degree 
Salometer  at 
64  Degrees 
Fahrenheit. 

Per  Cent  of 
CaCla. 

Freezing 
Point  in 
Degrees  Fah. 

*    2  11 

Ills 

«  **g. 

1.007 

1 

4 

0.943 

+31.20 

46 

1.014 

2 

8 

1.886 

+30.40 

45 

1.021 

3 

12 

2.829 

+29.60 

44 

1.028 

4 

16 

3.772 

+28.80 

43 

1.035 

5 

20 

4.715 

+28.00 

42 

1.043 

7 

24 

5.658 

+26.89 

41 

1.050 

7 

28 

6.601 

425.78 

40 

1.058 

8 

32 

7.544 

+  24.67 

38 

1.065 

9 

36 

8.487 

+  23.56 

37 

1.073 

10 

40 

9.430 

+22.09 

35.5 

1.081 

11 

44 

10.373 

+20.62 

34 

1.089 

12 

48 

11.316 

+19.14 

32.5 

1.097 

13 

52 

12.259 

+17.67 

30.5 

1.105 

14 

56 

13.202 

+15.75 

29 

1.114 

15 

60 

14.145 

+13.82 

27 

1.122 

16 

64 

15.088 

+11.89 

25 

1.131 

17 

68 

16.031 

+  9.96 

23.5 

1.140 

18 

72 

16.974 

+  7.68 

21.5 

1.149 

19 

76 

17.917 

+  5.40 

20 

1.158 

20 

80 

18.860 

+  3.12 

18 

1.167 

21 

84 

19.803 

—  0.84 

15 

1.176 

22 

88 

20.746 

—  4.44 

12.5 

1.186 

23 

92 

21.689 

—  8.03 

10.5 

1.196 

24 

96 

22.632 

—11.63 

8 

1.205 

25 

100 

23.575 

—  15.23 

•      6 

1.215 

26 

104 

24.518 

-19.56 

4 

1.225 

27 

108 

25.461 

-24.43 

1.5      . 

1.236 

28 

112 

26.404 

-29.29 

1'  '      vacuum    • 

1.246 

29 

116 

27.347 

—35.30 

5  '  '      vacuum 

1.257 

30 

120 

28.290 

-41.32 

8.5'  '  vacuum 

1.268 

31 



29.233 

-47.66 

12'  '      vacuum 

1.279 

32 

30.176 

-54.00 

15'  '      vacuum 

1.290 

33 

31.119 

-44.32 

10''      vacuum 

1.302 

34 

32.062 

-34.  «6 

4  '  '      vacuum 

1.313 

35 

33. 

-25.00 

1.5      pounds 

REFRIGERATING  EFFECT  OF  QNE  CUBIC  FOOT  OF  AMMONIA 

GAS  AT  DIFFERENT  CONDENSER  AND  SUCTION 

(BACK)  PRESSURES  IN  B.  T.  U. 


L 

IJ 

Temperature  of  the  Liquid  in  Degrees  Fahrenheit. 

*• 

IS* 

65°.      70°,     75°      80°      85°      99°      95°      100°      105° 

ii 

§11 

la- 

III 

Corresponding  Condenser  Pressure  (gauge),  Pounds  per  Square  Inch. 

Is 

n 

103        115      127        139      153      168        184      200       218 

-27° 

G.Pr«s 

27.30 

27  01 

26.73 

26.44 

26.16 

25.87 

25.59 

25.30 

25.02 

-20° 

4 

33.74 

33.40 

33.04 

32.70 

32.34 

31.99 

31.64 

31.30 

30.94 

—15° 

6 

36.36 

36.48 

36.10 

35.72 

35.34 

34.96 

34.58 

34.20 

33.82 

—10° 

9 

42.28 

41.84 

41.41 

40.97 

40.54 

40.10 

39.67 

39.23 

38.80 

—  5° 

13 

48.31 

47.81 

47.32 

46.82 

46.33 

45.83 

45.34 

44.84 

44.35 

0° 

16 

54.88 

54  .  32 

53.76 

53.20 

52.64 

52.08 

51.52 

50.96 

50.40 

5° 

20 

61.50 

60.87 

60.25 

59.62 

59.00 

58.37 

57.75 

57.12 

66.50 

10° 

24 

68.66 

67.97 

67.27 

66.58 

65.88 

65.19 

64.49 

63.80 

63.16 

15° 

28 

75.88 

75.12 

74.35 

73.59 

72.82 

72.06 

71.29 

70.53 

69.70 

20° 

33 

85.15 

84.30 

83.44 

82.59 

81.73 

80.88 

80.02 

79.17 

78.31 

25° 

39 

95.50 

94.54 

93.59 

92.63 

91.68 

90.72 

89.97 

88.81 

87.86 

30° 

45 

106.21 

105.15 

104.09 

103.03 

101.97 

100.91 

99.85 

98.79 

97.73 

35° 

51 

115.69 

114.54|  123.  39 

112.24 

111.09 

109.94 

108.79 

107.64 

106.49 

NUMBER  OP   CUBIC   FEET   OF   GAS  THAT   MUST   BE   PUMPED 
PER  MINUTE  AT  DIFFERENT  CONDENSER  AND  SUCTION 
PRESSURES  TO  PRODUCE  ONE  TON  OF  REFRIG- 
ERATION IN  TWENTY-FOUR  HOURS. 


1  ' 

iJ 

Temperature  of  the  Gas  in  Degrees  Fahrenheit. 

o£ 

IS? 

65°       70°      75°      80°      85°      90°      93       100°       105° 

Hi1 

Iflf 

Corresponding  Condenser  Pressure  (gauge),  Pounds  per  Square  Inch. 

f-9 

ll 

103       115      127      139       153       168       184       200        218 

G.  Pres 

—27° 

1 

7.22 

7.3 

7.37 

7.46 

7.54 

7.62 

7.70 

7.79 

7.88 

-20° 

4 

5.84 

5.9 

5.96 

6.03 

6.09 

6.16 

6.23 

6.30 

6.43 

—15° 

6 

5.35 

5.4 

5.46 

5.52 

5.58 

5.64 

5.70 

5.77 

5.83 

—10° 

9 

4.66 

4.73 

4.76 

4.81 

4.86 

4.91 

4.97 

5.05 

5.08 

—  5° 

13 

4.09 

4.12 

4.17 

4.21 

4.25 

4.30 

4.35 

4.40 

4.44 

0° 

16 

3.59 

3.63 

3.66 

3.70 

3.74 

3.78 

3.83 

3.87 

3.91 

5° 

20 

3.20 

3.24 

3.27 

3.30 

3.34 

3.38 

3.41 

3.45 

3.49 

.10° 

24 

2.87 

2.9 

2.93 

2.96 

2.99 

3.02 

3.06 

3.09 

3.12 

15° 

28 

2.59 

2.61 

2.65 

2.68 

2.71 

2.73 

2.76 

2.80 

2.82 

20° 

33 

2.31 

2.34 

20C 
.OD 

2.38 

2.41 

2.44 

2.46 

2.49 

2.51 

25° 

39 

2.06 

2.08 

2.10 

2.12 

2.15 

2.17 

2.20 

2.22 

2.24 

30° 

45 

1.85 

1.87 

1.89 

1.91 

1.93 

1.95 

1.97 

2.00 

2.01 

35° 

51 

1.70 

1.72 

1.74 

1.76 

1.77 

1.79 

1.81 

1.83 

1.85 

76 


DAILY    ELEVATOR    REPORT* 


Dat.p                                            Monroe  Street 

Hack. 
No. 

In 
Sirvioe 

Out  of 
Strvica 

Thai  Repair 

Time  OIT 

REMARKS 

1 

2 

3 

4 

5 

6 

7 

& 

ft 

it 

SUPPLIES    WANTED  

SIGNED.... 

Working  size  of  this  sheet  8x14. 
77 


ENGINE   No.   1.*          Month  of...  ...190... 


Hours     Cj'l 
Run       Oil 


.  Boars  Klee.  P.  Hoars 


Itmarks  and  Repairs 


Working  size  of  this  sheet  12x16 
78 


SWITCHBOARD    READINGS 


Date 


DYNAMO 
NO.  1 


DYNAMO 
NO.  2 


DYNAMO 
NO. 3 


DYNAMO 
NO. 4 


DYNAMO 
NO. 5 


AM.      Voltl 


1A.M 

2 

3 


TOTAL'AM AVERAGE  AM.   HRS 

TOTAL  K.  W READING  TOTAL  WATT  METER. 


AVERAGE  VOLTAGE 

*Working  size  of  this  sheet  9x13. 

79 


DAILY    BOILER    ROOM    REPORT* 


Date_ 


EQUIPMENT 

ON 

OFF 

DAYS  RUN 

VEEN 
WASHED 

CONDITION 

DRAFT  IX.    REMAMS  AND  REPAIRS 

In*. 

lit. 

Boiler  No.  1... 

Boiler  Ho.  2... 

Boiler  Ho.  3... 

Boiler  No.  4... 

Boiler  No.  5... 

STOKERS 

REMARKS  AND  REPAIRS 

No.  1  

No.  2 

No.  3 

No.  4  

Ho.5  

STOKER  FANS 

ON 

OFF 

HOURS 
RUN 

CON- 
DITION 

GIL.  OIL 
PTS. 

MACE. 
OIL  PTS. 

REMARKS  AND  REPAIRS 

Engine. 

Motor.. 

WJSBST1R 

HEATERS 

IH 

OUT     IDATSRUN 

CON- 
DITION 

WHEN 
CLEANED 

Compound 
Pounds 

REMARKS  AND  REPAIRS 

Ho.  1 



No.  2 

SAfiTY 
VALVES 

VEEN 
TESTED 

BLOWS 
AT  PRESS 

CON- 
DITION 

REMARKS  AND  REPAIRS 

No.  1  

io.a  

Ho.3  

No.  4  

Io.5    

NO.  OF  LOADS  OF; 
CARS  OF  COAL  BU 
CARS  OF  ASH  REh 
LOADS  OF  COAL  R 
WEIGHT  OF  COAL 
WEIGHT  OF  ASH.. 

ISH  REMOVED 
RNEO  • 

SUPPLIES  VJf 
GENERAL  RE 

1OVED 

ECEIVE 
BURNE 

D  
3  

riARKS  

FROM TO.... 


SIGNED 

"Working  size  of  this  sheet  12x16. 

80 


ENGINEER 


DAILY    ENGINE    ROOM   REPORT* 


Date_ 


EQUIPMENT 

STARTED 

STOPPED 

Hours  Ru 

Cylinder 
i      Oil 
Pts. 

REMARKS  AND  REPAIRS 

Engine  No.  1  .  . 
Engine  No.  2  .  . 
Engine  No.  3  . 
Engine  No.  4.. 

1 

Engine  lo.  5.. 



ELEVAiOR 
'     PDMPS 

STARTED 

STOPPED 

HoursRun  <ffj* 

REMARKS  AND  REPAIRS 

Pump  No.  1  ... 

Pump  No.  2... 

PumpKo.3... 
Pump  No.  4... 

ELRVATOR 

Auxiliaries 

BURIED 

STOPPED 

HoursRnn 

Cylinder 
Oi  Pts. 

REMARKS  AND  REPAIRS 

Pump  No.  1  ... 
Pump  No.  2  ... 





REFRIGERAT'G 

STARTED 

STOPPED 

HoursRun 

Condenser 
Press 

S.   W;  S  53!    R^^S  AND  REPAIRS 

Comp'rNo.  1.. 

JEED-UMPS 

STARTED 

STOPPED  HoursRun 

FeedWat'r 

5-s^ 

Pump  So.  1  ... 



Pump  No.  2  ... 

FILTER 

WHEN 
WASHED 

Condition 

HEATING 
SYSTEM 

EXHAUST 

LIVE 
STEAM 

a-*  y.  v»c 
3|i     I 

u'm  Pump  £ 

tarted  S-opped  Hr..RUn  .j^  „•  £  a  e  court  u.i,  n.i»   nm 

On        Off 

PumpS 

tarted  Stopped  H-.,..       '                 j^,po,,|o»|on|off 

GENERAL  REMARKS.-.. 


SIGNED 

..TO 

*Working  size  of  this  sheet  12x16. 

81 


ENGINEER 


TROUBLE  TICKET. 


DATE 


ROOM  NO. 


TIME    REC'D 


A.  M. 


P.  M. 


NATURE  OF  TROUBLE 


MATERIAL  USED 


TIME  0.  K. 

TIME  PUT  IN 

REPAIRED  BY 

A.  M. 

P.  M. 

RECEIVED  BY 


PHONE 


OFFICE 


'Working  size  of  this  sheet  6x9 
82 


INDEX 


Page 

Absorption    Plant 72 

Absorption    Refrigeration 40 

Air  Chambers  on  Discharge 27 

on    Suction 26 

"     Compressed    Pressure 36 

Temperature  of 37 

"     Compressor  Clearance- 36 

.  "                           Condensing            37 

"    Lifts .  36 

'     Pressure    in    Compressor 36 

Alternate    Method    Test 56 

A.  S.  M.  E.  Boiler  Trial  Rules 50 

Ammonia,  Aqua 40 

Compressor              40 

Gas 76 

Table   of 74 

Analysis    of    Coal 55 

"          of   Flue   Gases 55 

Apparent   Clearance  in   Compressor                        '.        .        .        .        .  36 

Aqua-Ammonia               40 

Artificial   Ice               41 

Ashes — 55 

Automatic    Damper    Regulator 35 

Engine n 

Auxiliary  Valves  on  Pumps .        .  29 

g^  &  W.  Boiler 18,  19,  20 

Back  Pressure,  Compound   Engine 13 

Bagging 23 

Balanced   Slide  Valve 6 

Belt — Double  Power  off 39 

Driven    Pump 29 

Belting             39 

Blister  on  Boiler  Plate 23 

Blowing  off   Point 19 

Blow-off    Pipe 18 

Boiler  and  Furnace        ...                34 

B.  &  W •  .        .        .        .     18, 19, 20 

Bag  in 23 

Blow-off                18 

Braces 18 

Cahall            21 

Circulation 18,22 

Crown    Sheet 16 

Cutting  in  of 19 

Drift  Pin .  16 

Efficiency .        .  •    34, 56 

Feeding  Economy 15 

Feed  Pipes,  Where  Placed     ....                .        .  20 


Boiler—  Feed   Pump,   How  to  Drive     . 
Feed    Water,    Hardness 
Furnace         
"          Headers     

Page 
29 

42 
34 
16 

Heads,  Dished      
"          Heine 

15 

2O 

Inspection             

Inspection   of   Brace        .... 

18 

Lap  Joint      

17 

Legs   Stays        

17 

Iowa               

23 

Lugs,  How  Attached       .... 

.        .        .        .            18 

"          Lugs 

18 

Man-holes          

15 

Mud    Drums         

.        .        .        .        16 

Plate—  Bag    in          

23 

Plate  Blistered     

23 

Plate    Straight          

24 

Pulsation    in         

14 

Put   into   Service     

19 

Report           

.        .        .        .        80 

Rivets 

M 

"          Rivets,    Strength          

15 

Seams         

15 

"          Staying      

16 

Stays              

14 

Stays,   Diagonal        

17 

Stays  —  in   Tension          .... 

18 

Steaming    and    Circulation 
Stirling                   ;         

22 

23 

"          Strain         .                 

2O 

Test       

50 

To  Lay  Up       

19 

Trial,   Rules          

50 

Tubes         

....                 14 

Tube    Caps            

16 

Tube  Split  to   Mend       .... 

21 

Tubes,   Straight  or  Curved 

16 

Water  Level  in        

22 

Braces,  Through        

18 

Breaker    Vacuum    

32 

Brine   Solution           

75 

Building  Ventilation       

70 

Butt  Straps,   How   Placed        .... 

15 

"      Strap  Joint,  Advantages  of          ... 

20 

Qahall  Boiler            
Calcium  Solution     

21 

75 

Caloric  Test 

55 

Calorimeter   Test           

42 

Card  —  Indicator         

41 

Cast  Iron  Mud  Drums          

19 

Caulking  Tools           

15 

Centrifugal    Pump 

28 

"      Suitable   for        .... 

28 

"      Work    in         .... 

25 

Chimney  Draft           

35 

Flues        

34 

H.   P.           .        

63 

Circulation    in    Boiler 

l8,  22 

84 


Page 

Clearance — as    Effected   by    Connecting    Rod 10 

Effect  on  Economy 6 

in   Air   Compressor 36 

Closed   Heater 31 

Coal  Analysis ' 55 

''     at    Test 50 

"     Burning  Furnace 34 

"     Cost   of,   &    Steam 34 

:     Moisture 54 

"     Ultimate  Analysis 57 

Cocks — Condenser 33 

Code  of  1899            50 

Cold  Water  Valves  for  Pumps 27 

Combustion,   Complete 34 

Compound  Gauge "...  43 

Engine 12 

Engines   Back    Pressure .13 

Engines  vs.  Simple      . 

Engine    Types 13 

Engines,    Why    Used 12 

Compressed  Air  Valves  for.  Pumps       .......  27 

Compression    Plant 72 

Refrigeration 40 

to    Change 5 

Compressor — Ammonia 40 

Clearance 36 

Condensing 37 

Condenser — Cooling    Surface    of 32 

Horse    Power 32 

Jet 12,31 

Jet  and  Surface 32 

Priming 33 

Surface 12,31 

Tubes 31 

Types  and  Uses            31 

Water  Per  Hour 32 

Condensing  Air  Compressor             37 

Engine  Cocks 33 

Condensing  vs.   Non-Condensing  Engines 8 

Connecting   Rod,    Length    of 10 

Connecting  Rod — Length — Effect  on  Guide  Pressure    ....  9 

Contraction  of  Steel  Tire 38 

Cooling  Surface  in  Condenser .  32 

Corliss    Valve 7 

Cost  of  Coal 34 

Cost  of   Steam 34 

Cost  to  Produce  Draft 34 

Covering — Pipe 65 

Crab  &  Bolt 22 

Crank    Angles 13 

Cross  Head  Pressure 9 

Head,  to  Disconnect 9 

Crown    Sheets            16 

Cut-off— Effect  of  a  Riding  Valve 6 

Four   Valve 7 

Four  Valve,  Two  Eccentrics 

Late  Advantages 8 

None   in    Duplex   Pump 27 

Single    Eccentric 7 

to   change 5 

85 


Page 

Cut-off  With   Slide   Valve  Engine 5 

Cushion    in    Pump 27 

Valve 28 

Cylinder — Temperature  Drop 41 

£)amper    Regulator 35 

Dash   Pots 8 

Deep    Well    Air    Lift 36 

Deep   Well    Pump 36 

Detachable  Valve  Gear  High  Speed 9 

Valve   Gear,   How   Closed        . 8 

Diagonal    Stay            14 

Stays,    Length    of 17 

Dimension    of    Pipes 64 

Discharge  Air  Chamber                27 

Air   Pressure 36 

Double   Belt,    Power    of .  39 

Draft— 35 

Forced 35 

From  Fan 35 

Gauge 42 

Induced 35 

Mechanical 35 

Mechanical,   Cost           .    • 34 

Drift  Pins 16 

Drilled  Holes 24 

Duplex  Pump  to  Set  Valves 27 

"           Pump-Stroke         .         ...         .         .         .         .         .         .         .  25 

Pump  Valve  Lap 27 

T7conomizer  and  Draft 35 

Fuel 31-34 

Tubes  to  Clean 33 

Economy— Effect  of   Clearance   on 6 

of   Feed   Pump 15 

of    Injector 15 

of  Steam  Pumps 25 

of  Super-heat  in  Steam 10 

of  Variously  Driven    Pumps 29 

Eccentric— Single  Cut-off 7 

Eccentrics — Advantage  of  Two       .        .        .  « 12 

Two   Cut-off 8 

1899— Code  of 50 

Efficiency  of  an  Injector 29 

of    Boiler 56 

"          of   Boiler   Furnace 34 

Electric  Elevator .        •  39 

Elevator— Electric 39 

High   Pressure  Hydraulic       ....  39 

"          Light  or  Loaded 39 

"          Passenger 39 

Plant .  39 

"          Report   from             77 

Engine — Automatic H 

Classes  of 12 

"          Clearance 10 

"          Compound 12 

Compound  Back  Pressure 13 

"          Compound   Types   of 13 

"         Compound,  Why  Used 12 


Page 

Engine — Condensing  Cocks 33 

Condensing  to  Start 32 

"           Condensing  with  two  Eccentrics      ......  12 

Condensing    or    Non-Condensing 8 

Economy    with    Superheat 10 

"          Four  Valve  Advantages 7 

Four    Valve    Cut-off 7 

Gas 38 

High  Speed  Valve  Gear 9 

Lead .  10 

Power  to  Change 9 

Report 78 

Room  Report 81 

Simple  vs.  Compound 8 

Slide   Valve 5 

Slide   Valve   Advantage 7 

Superheated  Steam  in 10 

Throttling n 

to    Change   Valve    Setting       " 9 

"          to  take  Charge  of 10 

Engineers — Duty 10-19 

Evaporation   Test 56 

Water,  Cost  of 34 

Exhaust  in  Compound  Engines  • 13 

pan  Draft 35 

Feed  Pipes 34 

Pump 15 

Water    Heater    &    Injector 29 

Hardness                       42 

Heater 33 

in  Economizer 35 

Pipes.  Location  of 20 

too    Hot   for   Injector 29 

Ferris    Wheel 38 

Fire    Protection 40 

Flues — Chimney              34 

Flue  Gases 55 

Fly  Ball  Governor  Failure 8 

Foot    Valve 27 

Force   Feed   Lubrication 8 

Forced  Draft      ' -35 

Lubrication 6 

Four  Valve  Engine  Advantages 7 

Cut-off 7 

Fuel  Economizer 31-34 

and    Draft 35 

Tubes — to    Clean 33 

Full   Stroke  Steam  in  Pump 27 

Furnace — Boiler 34 

Efficiency        .                                   34 

&  Boiler            34 

Fusible    Plugs 19 

Plug— to  Melt 21 

(~Jas — Ammonia 76 

Gas  Engine 38 

Producer 38 

Gauge.  Compound      .        .                 43 

Draft            42 

87 


Page 

Gauge,  Glass  &  Level 22 

Glass — Valve  Shut-off 22 

Loop .  42 

Pressure 42 

Gauges,  Pressure  and  Vacuum 43 

Globe  Valve,  How  Placed 40 

Governor — Belt  Break 8 

Defects  in            8 

Fly  Ball  Failure             8 

Inertia 11 

Range II 

Throttling             n 

Throttling  on  Gas  Engine 38 

Gravity  Heating  System 41 

Gridiron   Valve 7 

Guide  Pressure 9 

T-Iammer    Test 14 

Water 40 

Hand  Hole  Bolt,  to  Protect            22 

"       Crab,  Lost 21 

"        "          "        to    Protect 22 

"       Plate    Burned    off 21 

"      Riveting 24 

Height  of  Pump  Lift 26 

Heine  Boilers 20 

Heat  Balance 56 

"     in   Injector 50 

Heater  and  Injector 29 

"        Closed             33 

"       Open 33 

Heaters — Types 31 

Heating  Steam  Risers                                    , 71 

Heating  System,  Gravity 41 

System    Vacuum 42 

High  Pressure  Elevator 39 

Valves 39 

Horse  Power  for  Ventilation 7° 

"      of    Chimney 63 

"            "       "     Condenser            32 

Hot  Water   Pump 26 

to    an    Injector 29 

Valves    for    Pump 27 

"     Well    Temperature 32 

Hydraulic    Elevator 39 

Jce,   Artificial 41 

"     Transparent 41 

Indicator  Card  Long  as  Possible ,        .  41 

Induced    Draft 35 

Inertia    Governor .11 

Injector  and  Feed  Water  Heater 29 

Injector — Economy 15 

Efficiency 29 

Failure  to  Work 29 

Heat    in So 

How   it   Works 3° 

How  it  Uses  Steam .  29 

Principle    of 30 

With    Heater 33 


injector—  With    Hot   Water     

29 

Inspection  of  a  Boiler    

14 

Iowa    Boiler       

•   •     23 

J  et  Condenser         

12,31,32 

Kent    Chimney    Formulas        

•        63 

J^ap    Joint      
1     on  Pump  Valves     

17 
27 

Late    Cut-off    Advantages     

Laying  up  a  Boiler    

19 

Lead,   in   Steam   Engine        

10 

Unequal            

6 

Lift  of  a  Pump      

26 

Locomotive  Crown  Sheets        

16 

Stav    Bolts 

J7 

Lost  Motion  in  Valve  Gear     ........ 

'     .        28 

Lubrication  —  Force    Feed      

8 

Forced   System  

6 

Lugs  —  How  Attached    

18 

Material   of    

18 

JVJa  chine   Riveting        
Manholes  —  Reinforced        

24 
15 

Mechanical  Draft  Cost          

34 

Fan     

35 

Memoranda     

83 

Metal   Pump  Valves         

27 

Moisture  in  Coal    

54 

Motor   Driven    Pump 

20 

Mud  Drums    

76 

in  Brick  Work    

16 

of  Cast  Iron    

19 

"NJational    Presidents         
N.  A.   S.   E.   Directory          

49 
49 

N.  A.  S.  E.  Preamble               

49 

Non-Condensing  vs.  Condensing  Engines           .... 

8 

Office   Building   Elevator         
Open  Heaters          

39 

packed  Plunger  Pump     .        
Passenger   Elevator        .        .        .        .        . 

25 
39 

Pipe   Covering           

"      Suction 

•         65 
25 

Pipes—  Water  Hammer  in        

40 

Standard    Dimension        

64 

"         Pitting   in 

40 

Piston   Pump 

25 

Rod,  to  Disconnect      

9 

Valve  vs.  Slide  Valve      

6 

Pitting  in   Pipes         /.  . 

40 

Plant,   Elevator       

39 

Pluneer    Pump            
Poppet  Valves        

25 
7 

Poppet  Valves  and  Super  Heated  Steam            .... 

4! 

Pop  Safety  Valve  —  Failure  to  Close       ...... 

22 

Page 

Pop  Safety  Valves— How  Set 19 

Power  Driven  Pump 29 

of  Belt .  39 

'     Engine,   to   change 9 

for    Refrigeration     .        .                 72 

"       Required  for  Elevator         .  39 

Preamble  N.  A.  S.  E.           .                        49 

Pressure  Gauge 42 

of   Air    in    Compresser 36 

on  Guides 9 

"          on    Receiver 12 

of  Steam  in  Receiver 10 

Priming    Condenser 33 

Producer,   Gas 38 

Pulsation  in  Boilers 14 

Pump — Air    Chamber 27 

"       on  Suction 26 

Auxiliary   Valve 29 

Boiler  Feed 15 

Centrifugal            28 

Centrifugal  Work   Done   in _  25 

Cushion    in 27 

Valve 28 

Deep    Well 36 

Direct  vs.  Power  Driven 29 

Duplex    Stroke 25 

Economy            25 

for  Hot  Water 26 

Foot    Valve 27 

Height    above    Supply 26 

How   Lift  Water 26 

Piston    Type 25 

Plunger  Type 25 

Rotary 28 

Steam,  Full  Stroke 27 

Steam,  Size  for  Economy 25 

Strainer 25 

Suction    Pipe 25 

Valves— 27 

Lap           27 

"        Lost    Motion        .                 28 

To    Set .        .  27 

Punched   Holes 24 

Real   Clearance   in  Compressor 36 

Receiver  and  Cranks 13 

Pressure    in 10 

"         Pressure — Failure   of     .  12 

—Why  Used 13 

Refrigeration — 40 

Absorption   Process 72 

Compression  Plant 72 

Power  for 72 

Test 72 

Tonnage           72 

Regulator,    Damper 35 

Re-inforcing  Plates           18 

Riding  Cut-off  Valve 6 

Rivet  Holes— Punched  and  Drilled 24 

Spacing 14 

90 


Page 

Rivets — Double   Shear 15 

Single    Shear 15 

Size    of 14 

Strength 15 

Riveting — Machine   and    Hand 24 

Rotary   Pump 28 

Rubber  Pump  Valves 27 

Qafety  Valve  Blowing 22 

"         "       — Blow-off    Point 19 

Safety  Valve— Dead  Weight 24 

Tandem 24 

"          "          to  Set  Same 20 

Setting  Pump  Valves 27 

Shearing  Strength          .                 24 

Simple   vs.   Compound    Engines                .                 8 

Single  Eccentric  Cut-off 7 

Sizes  of  Pipes 64 

Slide    Valve,    Balanced 6 

'     Engine            5 

Advantages            7 

"    Lead 6 

"          "     vs.    Piston    Valve 6 

Smoke   During   Test 55 

Standard   Method   Test         .'........  56 

Stand  Pipes  for  Fire 40 

Starting    Condenser    Engine 32 

Stays — Diagonal    vs.    Through 14 

Stay  Bolts — 16 

Application   of 17 

Defective 17 

Steam  Air   Compressor 37 

Calorimeter,    Use    of 42 

Cost  to  Evaporate '34 

Drop  in  Temperature 41 

Gauge 42 

Heating  Risers 71 

In  an  Injector — How  Used 29 

Line  Pitting 40 

Pump  Auxiliary  Valve 29 

Pipe  Covering 65 

Pressure  in   Receiver 10 

Quality   of           .        .    • 53 

Radiation 71 

Superheat   Economy                   10 

Superheated            41 

Throttled  to  Pump  T 25 

Valves     .                         39 

Valves  on   Pump 27 

"      Velocity  in  Injector 30 

Steel  Tire 38 

Stirling  Boiler            23 

Strainer  for  Pump 25 

Strains  in  Boilers .20 

Stroke  of  Duplex  Pump      .                                          .         .  25 

Strength  Shearing 24 

Tensile 24 

"         Torsional            24 

Submerged  Tube   Sheet 18 

Suction,  Air  Chamber  on ,26 


Page 

Suction,  Foot    Valve 27 

"        Gas  Producer 38 

Lift 26 

of  Hot  Water     .  • 26 

Pipe 25 

Water— Grit  in 25 

Superheat  in  Steam — Economy  of 10 

Superheated  Steam  Defined     .                 41 

"       Disadvantages   of 41 

Superheater         ...                 31 

Surface  Condenser          .        .        . 12,31,32 

Switchboard   Report          ....                 79 

Air    for   Ventilation 70 

Ammonia      .                                          74 

Ammonia   Gas                   76 

B.  H.  P.  Evaporation 61 

Brine    Solution 75 

Building   Ventilation            70 

Calcium  Solution 75 

Coal  Heat  Value 62 

Coal  &  Oil         .        .        . 62 

Evaporation,  Factor  of 60 

Evaporation  per  B.  H.  P.       . 61 

Factor   of   Evaporation 60 

Flue   Velocities 71 

B.  H.  P.  Steam  Consumption 61 

Kent's  Chimney  Formulas 63 

Oil  and  Coal 62 

Pipe  Sizes 64 

Radiation 71 

Refrigeration,  Amount  of  Gas 76 

Report  on   Boilers 80 

Report  on  Elevator 77 

Report  on   Engine 78 

Report    of    Engine    Room 81 

Steam 66-70 

Steam  Consumption  for  I.  H.  P 61 

Steam    Discharges 62 

Steam.  Risers             71 

Switch   Board 79 

Trouble 82 

Ventilation            .        .        .        .        : 7° 

Tandem  Safety  Valves 24 

Tank  Heads  Dished 15 

Temperature  Drop  in   Cylinder 41 

in   Hot  Well 32 

of  Compressed  Air 37 

Tensile  Strength 24 

Test — Alternate    Method 56 

Evaporative 56 

"      Refrigeration 72 

"      Standard    Method 56 

Throttled  Steam  to  Pump     . 

Throttling  Engine 

"          Governor              ll 

"         Governor  or  Gas  Engine 38 

Tire,  Steel       .                        ...  38 

Tonnage   in    Refrigeration 72 

Tools,  Caulking 15 


Page 

Toi 

Trouble  Report       

.         .         .        ,        .        .   '         82 

True  Water  Level     

22 

Tube  Caps       

16 

" 

Headers,    nipple       .... 

16 

" 

Sheet  Submerged 

18 

" 

Split,   How  to   Mend 

21 

" 

Condenser              .... 

.....               31 

" 

Curved    or    Straight 

16 

" 

to  Fasten  in  Head 

14 

Tubular  Boiler  Inspection 

14 

Ui 

timate  Analysis  of  Coal 

57 

"yacuum      

32 

Breaker      

32 

Gauge            

43 

Heating  System 

42 

How    Lost             .... 

32 

Va 

ve,   Corliss         

7 

Cushion           

28 

for    Pumps          .... 

27 

Gear,  High  Speed         .        .     •  . 

9 

Gear  —  Detachable  —  How  Closed 

8 

High    Speed 

Lost  Motion  in 

Gears  and  Superheated  Steam     . 

41 

Globe,   How    Placed 

40 

High   Pressure       .... 

-        -        •        .        .        39 

Gridiron       

7 

Lap          

Piston          

5 

Poppet          .        .            .        ... 

7 

Setting  to  Change 

9 

Slide 

6 

Ventilation       

7° 

H.    P.   for 

70 

Velocity  in  Flues    

71 

' 

of   Steam  in    Injector 

.        .        .        30 

Ver 

tical    Boiler    Stavs 

17 

'yV'ater    Circulation   in    Boiler 

.       .       .       .        .        18 

"      —  Cost  to   Evaporate 

34 

Water  —  for  Condenser       .... 

32 

" 

in  Feed   Economizer 

35 

" 

Hammer              .           ... 

40 

" 

Hard  for  Boilers 

42 

" 

Hot  for  Pump      .... 

26 

" 

Hot  to  an  Injector 

29 

" 

Leg,    How    Stayed 

17 

" 

Level    in    Glass 

22 

" 

Sand  and  Grit   in       ... 

25 

" 

Suction      

25,26 

•' 

Supply    Below    Pump 

26 

" 

Tender    Duties 

IQ 

Tube  Boiler  Circulation 

18 

Headers 

16 

" 

Mud    Drums 

16 

" 

"          "       Tube  Caps 

16 

Well,    Hot    Temperature 

32 

Work   Done   in    Centrifugal    Pump 

25 

ELECTRICITY 


Page 

45 

Alternating  Current 44 

Alternating   Current   Generator        ....  ...  45 

Alternator,  to    Start   up 47 

Battery,   Storage 46 

Boosters  46 

Booster    Set 44 

(Compound  Wound  Generator 46 

"        Motor 47 

Conductor 45 

Constant  Current  Generator  47 

Converter,  Rotary 46 

Current — Alternating .44 

Direct 44 

Quantity 45 

Direct  Current 44 

J^conomical    Voltage 45 

Electric  Magnet 45 

Electric  Elevator  39 

"        Terms 45 

Elevator — Electric -    ...  39 

Explosion  of  Lamp 46 

JTields  of  Generator 45 

Field-  Strength  and  Speed      ........  4» 

Force,    Magnetic 45 

Frequency,  Changes 46 

Qenerator— Compound 46 

"          Constant    Current 47 

Field 45 

Jnduced  Magnet 45 

Induction  Motor 48 

T  amps    in    Series <  46 

'    Lead 47 

TV/Tagnet— Electric 45 

IVA  «      —Electro 45 

"          Induced  45 

Natural 45 

Magnetic  Force,  Limits  of 45 

Motor — Compound         ...  47 

Driven  Pump 29 

"          Induction  ...  48 

Series  .        .  47 

94 


Page 

Motor  —  Shunt         ....         .......  47 

Speeds  &  Field  Strength      ........  48 

"          Synchronous      ..........  48 

Natural    Magnet       ...........  45 

............  45 

Effect  on  Amperes               ........  45 

pilot  Lamp  Explosion           .........  46 

Potential       ............  45 

Resistance       ......                 ......  45 

Rotary  Converter       ..........  46 

gecondary  Windings               .                          ......  44 

Series  Lamps       ...........  46 

Series  Wound  Motor      ..........  47 

Shunt   Wound   Motor       ......        ....  47 

Solenoid  —  Purpose  of     ..........  44 

Step  Down  Transformer       •    .        .        .        .        .        .        .        .         44.  46 

"       Up    Transformer         .........  44 

Storage  Batteries       ...                 .......  46 

Sub-Station  Apparatus           ........         .  46 

Synchronous   Motor           ........  48 

'transformer  —       .....        .         .....  44 

Step  Down       .........  46 


..............  45 

Voltage         ............  45 

Voltage—  Combined  Load      .........  45 

Windings  .....        ,        ......  44 


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TJT 


THE  LIBRARY 
UNIVERSITY  OF  CALIFORNIA 

Santa  Barbara 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW. 


UC  SOUTHERN 


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